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WATER and AIR QualityManagement

- INDIAN PERSPECTIVE


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ANURAG ARYA (202)


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RASHMI MEHTA (208)


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RAHUL GUHA (218)


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NEHA SUMAN (215)


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J ATIN NAGPAL (211)


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GAURAV MATHUR (207)


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AYON CHOWDHURY (203)


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Management of Environment Definition of Environment

The surroundings in which an organisation operatesincluding air, water, land, natural resources, flora, fauna,humans and their interrelation

"environment" includes water, air and land and the inter-relationship which exists among and between water, airand land, and human beings, other living creatures,plants, micro-organism and property


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Management of Environment Sustainable development

Meeting the needs of the present generation without compromising theability of future generations to meet their own needs


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Management of Environment Global Environmental issuesGlobal warming

Ozone depletionDisappearance of tropical forestsDwindling varieties of wildlifeMarine Pollution

Transboundary movement of Hazardous WasteDesertification Acid RainEnvironmental Pollution in economically developingcountries


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Management of Environment Global warming

Global warming is a process in which the surface temperature of theEarth rises because of the "greenhouse effect." The greenhouseeffect is caused by an increase in greenhouse gases (carbon dioxide,methane, chlorofluorocarbons, etc.), which we produce as we goabout our daily life.

The results of global warming are predicted to be higher sea levels,as the seawater expands from the heat, and harsh climatic changes.These changes are expected to exert a big effect on agriculture andecosystems.


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Management of Environment Ozone Layer Depletion

Ozone is a natural gas that exists in large quantities in thestratosphere, which is one of the upper layers of the Earth'satmosphere. There, ozone works to protect life on earth byabsorbing ultraviolet rays and other harmful rays from the sun. Thisozone layer is steadily being destroyed by chlorofluorocarbons,halons and other ozone-depleting substances in the atmosphere.

As the ozone layer is destroyed, more harmful ultraviolet rays reachthe Earth's surface. This causes skin cancer, cataracts and otherhealth problems and may exert dangerous effects on plankton,agricultural products and all kinds of plants and animals.


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Management of Environment Acid Rain

Since the industrial revolution, we have been using large quantitiesof oil, coal and other fossil fuels. The combustion (burning) of fossilfuels generates large amounts of sulfur oxides and nitrogen oxides.

Acid rain is rain (or mist) that has picked up these oxides, whichhave been released into the atmosphere, and deposits them on theground.

In Europe and North America, acid rain and acidification of the soilis promoting the disappearance of forests and the deterioration of historical ruins and other structures. The acidification of lakes andmarshes there is causing the extinction of certain fishes and havingother ill effects.


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Management of Environment Disappearance of tropical forests

Tropical forests are an important source of lumber. At the same time,tropical forests serve the vital role of being wildlife habitats and of absorbing and storing carbon dioxide, which is the main cause of global warming. It is estimated that about 1,540 hectares of tropicalforest disappear each year, because of large-scale, slash-and-burnagricultural practices and logging for commercial purposes.

The disappearance of tropical forests is raising concerns about thelarge-scale extinction of certain species of wild life, the destruction of ecosystems, and effects on global warming.


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Management of Environment Dwindling variety of wildlife

There are about 1.75 million species of wild life on this planet that

have been verified scientifically. The actual number of species

could be 10 million or maybe even more than 100 million! But the

destruction of wildlife habitats by human activity and the

indiscriminate catching and killing of wildlife is causing a sharpdecline in the number of wild plants and animals on this planet.

This trend is causing concern regarding the loss of precious gene

pools and changes in ecosystems.


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Management of Environment Marine Pollution

Pollution of the Earth's oceans and seas is getting worse. Pollutants

are flushed down rivers and streams, and oil spills into the water

when tankers and other ships collide and through off-shore drilling

and other marine resource development. This pollution exertsharmful effects on fish and birds, and the resultant "red tides" cause

problems for fisheries.


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Management of Environment Transboundary movement of Hazardous Waste

Expanded human activity has brought with it an increase in the

volume of waste generated. The cost for handling this waste has

also skyrocketed. This has led industrialized nations to take some of

their waste, including recyclable waste, to developing countries. But

this waste also contains toxic substances. When the waste is not properly treated, it pollutes the rivers, groundwater and soil of these

economically developing countries and becomes an international

problem.


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Management of Environment Desertification

Desertification (the changing of productive land into barren land)occurs for various reasons: When regions dry out because of adecrease in rainfall caused by climatic changes; when land is over-cultivated, overgrazed or too many trees are taken for firewood,because of increasing populations in economically developingcountries; when land is not given enough time to rest betweenplantings and becomes barren; and other reasons.Today, desertification effects about one-fourth of the Earth's landsurface and about one-sixth of its human population (or 900 millionpeople).


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Management of Environment Environmental Pollution in developing countries

In economically developing countries, transportation facilities,sewers, waste treatment facilities and other parts of the basic

infrastructure cannot keep pace with the rapid increase in

population and the tremendous influx of people into cities.

Also, anti-pollution measures at factories and other places are

often insufficient, resulting in a deterioration of the general

hygiene and a worsening of air, water and other forms of

pollution.


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Management of Environment Major environmental issues in India

Intensive agricultural practicesDegradation of soils due to overuse of chemicals,

fertilizers, mono culture

degradation of groundwater quality

increase in the use of pesticides leading to health

hazards, and decline in crop diversity.


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Population explosion

The failure to realize the link between poverty andenvironmental sustenance

All these factors have snowballed into major environmentalproblems such as decline in forest cover, increased soilerosion, silting of reservoirs and lakes, decline in biodiversityetc.,

Problems related to industrialization and urbanization


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Lopsided development policies have resulted indegraded soils, depletion of water tables, increasedfloods, desertification, water logging and salinity,pollution of water and air and loss of biodiversity.

Adoption of less environment friendly technologies

Unchecked growth of the informal manufacturing

sector


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Management of Environment Environmental Legislation in India

The Water (Prevention and Control of Pollution) Act, 1974 (1988)

The Water (Prevention and Control of Pollution) Cess Act,1977(1992, 2003)

The Air (Prevention and Control of Pollution) Act, 1981 (1987)

The Environment Protection Act, 1986 (1991)

The Environment Protection Rules, 1986 (1998,99,2001,02,03,04,06)


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Management of Environment Environmental Legislation in India (contd)Coastal Regulation Zone (30 notifications)Delegation of powers (16 notifications)Eco-mark scheme (2 notifications)Eco-sensitive Zone (10 notifications)

Environmental Clearance (with 6amendments)Environmental Labs (1 amendment)


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Management of Environment Environmental Legislation in India (contd)

Hazardous Substances Management

The batteries (Management and Handling) Rules, 2001

The Municipal Solid Waste (Management and Handling) Rules,

2000

The Recycled Plastics Manufacture and Usage Rules, 1999 (2003)

Prohibition on the handling of Azodyes (1997)

The Chemical Accidents (Emergency Planning, Preparedness and

Response) Rules, 1996


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Hazardous Substances Management

The Rules for Manufacture, Use, Import, Export and Storage of

Hazardous microorganisms, genetically engineered organisms or cells

(1989)

MSIHC Rules, 1989 (2000)

The Hazardous Waste (Management and Handling) Rules, 1989 (2000,

2003)

The Bio-medical Waste (Management and Handling) Rules, 1998 (2003)


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PLI Act, 1991 (1993) and rules (and 5 notifications)The Prevention of Cruelty to Animals Act, 1960

The Wildlife Protection Act, 1972 (1993, 2002)

The Indian Forest Act, 1927

The Forest Conservation Act, 1980 (1988)

The Biodiversity Act, 2002


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Management of Environment StakeholdersGovernment NGOsIndustries

General Public


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TREATMENT


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TREATMENTPurpose: To remove the contaminants from water so

that the treated water can meet the acceptable

quality standards.Water treatment consists of three stages:

a) Primary treatment

Primary treatment comprises of pretreatment andsedimentation step.

a) Secondary treatment

b) Tertiary treatment


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TREATMENT

Treatment can be classified as:1. Physical2. Chemical3. Biological


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PHYSIC AL

Based on exploitation of physical

properties of contaminants.Simplest form of treatment

Comprises of screening, sedimentation,floatation and filtration.


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CH EM IC AL

Chemical properties of impurities oradded reagents are utilized.Commonly used processes are:precipitation, coagulation anddisinfection, air stripping, carbonabsorption, oxidation and reduction,ion exchange and membraneseperation.


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B IO LOGIC AL

Biochemical reactions are utilized.Biological filtration and activatedsludge process are important process.


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P RETREATMENT

To remove large floating and suspended solids that

interferes with normal operation of subsequent

treatment.

It may also include flow measurement and sometimes

chlorination to prevent odours that may emanate in

subsequent processes.

It mainly consists of screening and grit removal.


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SC REEN I NG

Screens of different shapes and sizes are used depending on thetype of solid to be removed.Screens are either manually or mechanically cleaned.Bar screens are the most commonly used screens, they are eithermanually raked or mechanically raked.They are parallel metal bars having aperture size of 20 60 mmfor manually racked & coarse screening and 10 20 mm for finescreening & mechanically raked.Screening produces material that must be disposed off insatisfactory manner that may include incineration, burial, grindingor digestion.


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G R I T CH AM B ER

Grit Chambers are generally long chambers, with very low inlet

velocity of waste water so as to facilitate the settling of grit.

The grit can be removed by scrapping.

Grit consists of sand, gravel, cinders and pebbles.

Grit chambers are preceded by screens

Grit chambers are provided to protect pumps from abrasion and toreduce the formation of heavy deposits in pipes and channels.

When comminutors are used than it is preceded by Grit Chamber.


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CO MM I NUT O R S

Comminutor is the device used to avoid disposal

problems faced by screening.It replaces screening

Comminutors grind larger solids which can later

be handled by sedimentation tanks.


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SED I MENTAT IO N

Settleable solids are removed by gravity settling under quiescentconditions.

The sludge is formed at the bottom of the tank and is removed byvacuum suction or by raking it to the discharge point at the bottomof the tank for withdrawal.

The clear liquid known as overflow is removed from top. It shouldnot contain readily settleable particles.

Minimum time spend by the liquid in settling tank is 2 3 hrs.


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SED I MENTAT IO N

Three types of flow is possible in the settling tank:Rectangular horizontal Flow: Feed is introduced at one end along the widthof the tank and the overflow is collected at the surface across the otherend. An endless conveyor scrapper is used to scrape the floating materialand pushes it into sludge trough/hopper.

Circular radial Flow: Feed is introduced through a centre well and theclarified effluent is collected at the weirs along the periphery of the tank.Sludge removal occurs by the help of rotary sludge scrapper which forcesthe settled sludge down a sloping bottom into the central hopper, fromwhere it is withdrawal. Often used in large ETPs.

Vertical Flow: Feed enters at a point along the bottom and the clarifiedeffluent is collected at top. A sludge blanket is maintained in the lowerpart of the tank through which suspension rises. It is important to bleed

the sludge timely so as maintain the desired blanket which acts as a filterfor smaller particles. Used in small ETPs.


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SETTL I NG TH EO R Y D iscrete Particle and flocculent particle behaviour are the two particles behaviourthat occurs in sedimentation tanks.

The discrete particle behaviour, particles do not interfere with one another their

shape, size and mass remains constant during settling.To remove large floating and suspended solids that interferes with normal operationof subsequent treatment.

In flocculent settling the particles agglomerate during the settling and do not possesconstant characteristics.The settling of particles in suspension depends on the concentration and theflocculating properties.

Three types of settling are recognized:Settling of discrete particlesSettling of flocculant particlesZone settling which includes hindered and compressive settling.


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D ISC RETE SETTL I NGParticle settling is unhindered by the presence of other settlingparticles.Settling is Function of properties of the fluid & the particle inconsideration.When discrete particle is placed in liquid of lower density, it willaccelerate until terminal velocity is reached.Vt = Q/AQ/A = Overflow rate which forms basis for evaluation of performanceof sedimentation tank.The rate of removal for a given discharge is independent of depth butis directly related to surface area.When Vs < Vt : the particle will not be removed during the timeprovided for settling since it does not reach the bottom of settlingzone.

When Vs > Vt : particles can be completely removed.


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F LOCC ULENT SETTL I NG

It occurs when settling velocities of particlesincreases due to coalescence with other

particles.

Coalescence increases with increase in beddepth and overflow.

This phenomenon is clearly observed in primaryclarifiers.


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Z O NE SETTL I NG

It occurs when suspension is dense and the particles are so

closely placed that the velocity field of fluid displaced by the

adjacent particles during settling overlap.

There is upward displacement of fluid with the reduction in the

settling velocities of the particles. (hindering effect)

It occurs at very high concentrations where the suspension tendsto settle with distinct interface between the settling solids and

the clear liquid above it. (zone settling)

This type of settling is observed in activated sludge process.


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Z O NE SETTL I NG4 zones are clearly observable:

Initially the solid concentration is uniform, but with time a clear liquid

forms at top and an interface develops.Zone A: Clear Liquid.Zone B: Uniform Concentration: Hindered settling condition occurin this zone.Zone C: Transient Zone: The velocity decreases due to high

concentration of solids.Zone D: Sludge : The main mechanism is compressive settling asthe solids are supported mechanically by the particles beneaththem.

Ultimately only two zones remain viz clarified liquid and sludge.


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Sampling and Measurement Two methods:

1) Ambient air quality measurement 2) Stack sampling


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Ambient air quality measurement Objective: 1. to obtain genuine and representative sample

2. Analytically measurable sample.

A typical air sampling system consists of asample collector,a flowmeter to measure the airflow through it anda pump to draw the air through it.

The function of sample collector is to retain the desired pollutant alone or as a mixture.

Choice of collector depends on:Nature of pollutant

Method of analysis


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SamplingGaseous PollutantsParticulate Pollutants


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Gaseous Pollutants

Gaseous Pollutants

Grab

Sampling

Absorption inLiquids

Adsorption onsolids

Freeze out sampling


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Grab SamplingThe sample is collected an evacuated flask or an

inflatable bag.

Is subjected to losses caused by moisture condensation

or diffusion through the walls of bag

Involves analysis immediately after collection

Plastic bags or rigid wall containers are used for this

purpose.


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A bsorption in Liquids

Most common method employed

Separates the desired pollutant from airDirect solubility in absorbing medium or by

chemical reaction.

Types:

Fritted Glass absorbers

Impinger


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Adsorption on solids

A ir sample is passed through a packed column containing a

finely divided solid adsorbent on whose surface the pollutants

are retained.

A ctivated charcoal and silica gel with very large surface area

are commonly used adsorbent.

A fter adsorption the sample gases are desorbed for analysis.

This is done by heating the adsorbent or by washing it with

liquid solvent.


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F reeze out sampling

A series of cold traps, which are maintained at progressively lowertemperature are used to draw the air samples whereby the pollutantsare condensed.

The sample is then analyzed using gas chromatography or infraredor ultraviolet spectrophotometer

Coolants commonly used are Ice water (0), Ice salt (-21), Dry ice A cetone (-79), Liquid A ir (-147), Liquid Oxygen (-183), LiquidNitrogen (-196)

Disadvantage is ice accumulation due to condensation of water

vapour thus plugging the system.


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Particulate Pollutants

Particulate Pollutants

Sedimentation

Hi Volumefiltration

Tape Sampler

Impingement

ElectrostaticPrecipitator


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SedimentationSimplest device used for particles larger than 10m size.

Inexpensive and requires no moving parts, electrical supply

Consists of a plastic jar 20 35 cm in height and 10 15 cm in dia

with slight taper towards bottom of the jar.

The sample is deposited over a period of one month and the

material is dried and weighed.

Samplers must be closely spaced for useful data.

Disadvantage is the method lacks precision and time consuming.


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Hi Volume filtration

Used for measurement of mass concentration of suspendedparticulates smaller than 10m.A known volume of air is sucked by a high speed blower through afine filter and the increase in weight due to the trapped particles ismeasured.The filter is made up pf fibrous or granular material which provides adense porous medium through which an air stream must changedirection in random fashion, allowing the entrained particle to impacton the filter material. Normally a glass fiber filter is used, it gives theefficiency of 99%.The sampling time is 24 hours and around 2000m3 of air is suckedthrough the filter.

The particulate level is measured in terms of gm/m3 of air.


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Tape SamplerSoil haze particle sampler is another name of this method.

A known volume of air is passed through a paper tape which is

advanced at certain interval from supply reel to take up reel.

During the sampling period the tape is held stationary.

The air is passed through nozzle and the particulates are

collected on the paper tape forming a spot.

Spot thus obtained are evaluated by analyzing the amount of

light that can be transmitted through the spot.


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Tape SamplerIt is measure as CO H /1000ft where CO H is coefficient of optical haze.COH is based on optical property hence it measures only degree of pollutants.Ex. 0 0.9 : Light; 1 1.9 : Medium; 2 2.9 : H eavy, etc.A nother method is ray attenuation which helps in determining the massconcentration of particulates.In this case the beam of particles of constant source with intensity Io ispassed through tape.By measuring the intensity Ic and I p of radiation that pass through cleantape and spot respectively, the mass of particulate matter per unit area of thespot can be evaluated.


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ImpingementWet impingement gives a greater efficiency.A gas stream at high velocity impinges on a flat surface

submerged in liquid.The gas breaks up into small bubbles and the particles arecollected by change in direction of gas flow and promotingtheir contact with liquid.Usually used for size > than 1m.The liquid is than filtered and the particulates dried.In dry impingement the evaporation / filtration is avoided.


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ImpingementCascade impingers are used, it contains 5 10 collectionstages in which sample air stream is constrained to passthrough a series of jets where pollutant particles are directedagainst collection surfaces placed normal to jets.Particles smaller in size with lower momentum is collected inlater stages due to high jet velocity.F ilter is placed after last stage to collect the fine particles.A fter sampling the material collected at each stage is weighed.Used for size upto 0.2 m.


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Electrostatic PrecipitatorNegative charge is imparted to a wire placed axially inside a

cylinder which is positively charged.

When the air stream passes through the cylinder, the particles

acquire a negative charge due to wire, and migrate towards

the inner surface of the cylinder.

It gives good separation of particles in size range of 0.01 0.2

m.


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BibliographyWebsites

www.unep.orgwww.envfor.nic.in

www.cpcb.nic.inwww.worldbank.org/nipr/indiawww.teriin.orgwww.narmada.orgwww.sanctuaryasia.com

www.undp.orgwww.iema.net

BookEnvironmental Management by Dr Balakrishnamoorthy


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