air pollution and its control through biotechnology

A SEMINAR ON AIR POLLUTION AND ITS CONTROL THROUGH

BIOTECHNOLOGY

BY-MISS. HUMA NAZ

SIDDIQU (ASST. PROF.)

G.D. RUNGTA COLLEGE OF SCIENCE AND TECHNOLOGY KOHKA KURUD ROAD BHILAI, 490023

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AIR POLLUTION AND ITS CONTROL

SYNOPSIS

INTRODUCTION

AIR POLLUTANTS

METHOD FOR ESTIMATION OF POLLUTANTS

METHOD USED FOR AIR POLLUTION CONTROL THROUGH BIOTECHNOLOGY BIOTECHNOLOGY METHODS FOR MANAGEMENT OF POLLUTION

SUMMARY

CONCLUSION

REFERENCE

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AIR POLLUTION AND ITS CONTROLINTRODUCTION

What is air pollution?Air pollution is the introduction of particulates, biological molecules or other harmful materials into the earth’s atmosphere, possibly causing disease, death to humans, damage to other living organisms such as food crop, or the natural or built environment.

•Air monitoring-The harmful effects of air pollution can be assessed only on the basis of adequate data collected at properly selected sampling stations using:- Well defined sampling proceduresAnalytical techniquesPhysiochemicalBiological monitoring 3


AIR

POLLUTANTS 4

Gravitytechniques

Greatsampling

Particulates Gaseous Pollutants

Filtrationtechniques

Precipitationtechniques

Coldtrapping

Absorption Adsorption

Thermalprecipitation

Electro staticprecipitation

Air Pollutants

AIR POLLUTION AND ITS CONTROLAIR

POLLUTANTS

Particulates- They are tiny pieces of solid or liquid matter associated with the earth’s atmosphere.1. Gravity techniques- It is used to collect settleable particulates in air. Device include dust fall sampling instrument, such as dust fall bucket, dust fall jar etc.

2. Filtration technique- It is used for collecting suspended particulates that do not settle out early. Devices used include high volume sampler, paper tape sampler, etc.

3. Precipitation techniques- Thermal precipitation- When exposed to a high

temperature gradient, suspended particles tend to move to lower temperature region. 5


POLLUTANTS

Electrostatic precipitation- In this technique, electrical charge is used to force radioactive or other particulates in the range of 0.001µ to 10µ to migrate out of the air stream onto a collecting surface.

2.Gaseous pollutants-The major gaseous pollutants include sulphur dioxide, carbon monoxide, and nitrogen oxide as well as ozone.

i. Cold trapping- In this technique, the gaseous pollutants from the air stream are trapped in different collecting chambers, each maintained at progressively decreasing temperature, ranging from 0˚C(in ice bath) to -196˚C(in liquid nitrogen bath).

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POLLUTANTS

ii. Absorption sampling- In this technique, the desired gaseous contaminant in air is collected by closely contacting with or bubbling through the corresponding absorbent solution.

iii. Adsorption sampling- In this technique, gases and vapours in the polluted air are adsorbed on suitable adsorbents eg. Activated charcoal, activated carbon.

iv. Great sampling- In this technique, a great sample is taken out between suitable intervals and is allowed to come into contact with a suitable absorbing solution in the sampling apparatus.

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METHOD

1. Dust fall jar-

Fig.No.1.-Dust fall jar 8


METHOD

2.Determination of suspended particulates with a high volume sampler-

Fig.No.2.-High volume sampler, for collecting atmosphere particulates matter. 9


METHOD

3. Determination of sulphation rate- Sulphation rate is a cumulative index useful for evluating S02 and other sulphur compounds in the atmosphere. it is determined by lead peroxide method.

4.Estimation of hydrogen sulphide- A measured volume of air at a suitable flow rate is passed through an absorbing solution containing CdSO4 and NaOH, taken in an impinger or an absorption bottle.

5.Analysis of carbon monoxide- Carbon monoxide strongly absorbs I.R radiation at certain wavelength. Hence it can be determined by non-dispersive infra-red spectrometry.

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METHOD

Source Typical pollutant emissions

Petroleum refineries and petrochemical industry

CO, particulate matter, smoke, hydrocarbon, odours of mercatans.

Iron and steel industry

SO2, CO, dust, particulates, acid fumes, odours, smoke, NO2.

Cement industry Cement, lime dust, fly ash, smoke.

Automobiles Smoke, hydrocarbon, HCHO.

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Table No.1- Pollutant emission


CONTROL

1.Zoning- The zoning of the industries is done on basis of the type of industries, their functions etc. zoning prevents the invasion of desirable industries in industrial areas and harmful gases are prevented from entering the atmosphere.

2.Control at the source- The air pollution can be prevented at the source by the change of raw materials or by the alteration in the equipment or by the modification of process or by the separation of pollutants at source. 12


CONTROL

3. Control by different devices-I. For particulates- CONTROL DEVICES FOR PARTICULATE MATTER

spray tower

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Internal separators wet collector devices electrostatic device

Gravity cyclone fabric Settling collector filterchamber

Cyclonic venturi packedScrubber scrubber bed scrubber


CONTROL

1. Gravity settling chambers-

Fig.No.3 - Gravitational settling chambers

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CONTROL

2.Cyclone collector-

Fig.No.4 –cyclone collector

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CONTROL

3.Fabric filters-

Fig.No.5- Fabric filter16


CONTROL

4. Spray towers-

Fig No.6:-spray tower 17


CONTROL

5. Cyclonic scrubber-

Fig.No.7-Cyclonic scrubber18


CONTROL

6.Venturi scrubber-

Fig.No.8-venturi scrubber19


CONTROL

7. Packed bed scrubbers-

Fig.No.9- packed bed scrubber 20


CONTROL

8. Electrostatic precipitator-

Fig No. 10:- Electrostatic precipitator21


CONTROL

2. For gaseous emissions-gaseous pollutants can be removed from air stream by the following techniques-

1.absorption and adsorption

Table No.2- Different adsorbent and their uses 22

adsorbent UsesActivated carbon

Removal of odors and trace impurities from gases, purification of industrial gases and hydrocarbon.

Activated alumina

Dehydration of gases and liquids

Silica gel Dehydration and purification of gasesBone charcoal Far decolorizing sugar solutions


CONTROL

2.Condensation- At a given temperature condensation of a compound will occur if its partial pressure is increased till its vapour pressure condensation is possible if gases temperature reduced to its saturation temperature and pressure is equal to its vapour pressure.

By the chemical alteration of the pollutant through combustion or catalytic treatment.1.Combustion-Combustion is a process in which a substance reaches its kindling point(a temperature where any substance catches fire or burn).There are three methods of combustion process-a) Direct combustionb) Thermal incineration or flame combustionc) Catalytic oxidation

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CONTROL

3.Control by stacks- Small quantities of air pollutants can be absorbed by the atmosphere but large amount of pollutants cannot be absorbed and cause serious problem in the atmosphere. The pollutants are taken to a high altitudes by means of stocks.

4.Control by planting trees and vegetation- It has been found that the planting trees is very helpful in reducing air pollution due to flyash and coal dust. So more trees should be planted all around.

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MANAGEMENT

The different approaches for the management of environmental pollution are describe by :-Atmosphere CO2 reduction- The reduction in atmosphere CO2 concentration assumes significance. There are mainly two approaches for the biotechnological reduction of CO2 in the atmosphere.1. Photosynthesis2. Biological calcification,

3. Microalgal photosynthesis- certain microalgae are more efficient than higher plants in utilizing atmosphere CO2 for photosynthesis.

• These organisms are capable of generating more O2 than the amount of CO2 consumed.

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MANAGEMENT

• Growing microalgae in the vicnity of industries and power plants where the production of CO2 is very high will help to minimise the polluting effects of CO2.

2. Biological calcification to reduce atmosphere CO2- Certain organisms present in the deep sea ( corals, green and red algae) are capable of storing CO2 through a process of biological calcification. As the CaCO3 gets precipitated, more and more atmospheric CO2 can be utilized for its formation.

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SUMMARY

Fig.No.11.- Air pollutionSmog hanging over cities is the most familiar and obvious of air pollution.But there are different kinds of pollution some visible some invisible that contribute to global warming. 27


CONCLUSION

Air pollution is known as a substance in the air that cause harm to humans and the environment.

Pollutants can be in the form of solids particles, liquid droplets, or gases.

Carbon dioxide, a green house gas, is the main pollutant that is warming earth.

Air pollutants at source level may be controlled by separating the pollutants from the harmless gases, and by converting the pollutants to innocuous product before their release in the atmosphere.

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REFERENCE

Indu shekhar thakur

2 nd edition Environment biotechnology, basic concept and application

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air pollution and its control through biotechnology

Education