|
 Environmental
Aspects
To get answers to the following questions on
environmental aspects, please select one of the links
below:
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| 1. |
What are the present
emission standards for foundry units? |
| 2. |
What is the emission standard
for foundry units in the UK? |
| 3. |
Why is particle size analysis
important and how is it done? |
| 4. |
How are the roles of Green
Bench and Appellate Authority different from each other? |
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|
| 1. |
What are the present emission standards for
foundry units? |
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Existing emission standards for foundries prescribed
by Central Pollution Control Board (CPCB) are given
below. |
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| Type |
Pollutant |
Concentration (mg/Nm3 ) |
I. Cupola capacity (melting rate) :
less than 3 Mt/hr
3 Mt and above |
Particulate matter Particulate matter |
450
150 |
| II. Arc furnaces capacity : all sizes |
Particulate matter |
150 |
| III. Induction furnaces capacity : all sizes |
Particulate matter |
150 |
Note:
1. It is essential that stack is constructed over
the cupola beyond the charging door and the emissions
are directed through the stack which should be atleast
six times the diameter of cupola.
2. In respect of arc furnaces and induction furnaces
provision has to be made for collecting the fumes
before discharging the emissions through stack.
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Source: EPA Notification, G.S.R. 742 (E), dt. 30 th
August, 1990
Emission standard for SO2 from cupola furnace is prescribed
to be 300 mg/Nm3 at 12% CO2 correction as referred in
MOEF notification dated 2nd April, 1996, New Delhi.
To achieve the standard, foundries may intake scrubber,
followed by a stack of height six times the diameter
of cupola beyond charging door. In case due to some
technical reasons, installation of scrubber is not possible,
the value of SO2 to the ambient air has to be effected
through the stack height. The rule to be called the
Environmental (Protection) Act, 1996.
Note: State Pollution Control Boards has powers to
make the emission norms more stringent, if required.
For example, West Bengal Pollution Control Board (WBPCB)
has revised the norm within the Kolkata metropolitan
area to 150 mg/Nm³ for all cupolas since May, 2001.
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| 2. |
What is the emission standard for foundry units
in the UK? |
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Emission standards for hot and cold blast cupola prescribed
by EPA, UK are given below. The standard are for particulate
matter only and thee are no standards for gaseous pollutants.
Emission standard for foundry prescribed by EPA, UK
|
| |
| Type |
Pollutant |
Concentration (mg/Nm3 ) |
New cupola (Oct,1991):
Hot and cold blast
New cupola (April,1997):
Hot and cold blast |
Particulate matter
Particulate matter |
100
20 |
Existing hot blast cupola (1991)
Existing hot blast cupola (1997) |
Particulate matter
Particulate matter |
115
100 |
Exiting cold blast cupola Capacity :
less than 4 tonne/hr
4 tonne/hr and more (1991)
4 tonne/hr and more (1997) |
Particulate matter
Particulate matter |
No standard
115
100 |
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| 3. |
Why is particle size analysis important and
how is it done? |
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Particle size distribution of the flue gases is the
most important guiding factor for selection of pollution
control devices. However accurate determination of particle
size distribution of the stack flue gases is a difficult
task. Normally ‘U shaped’ thimble or other
glass fibre filter papers are used during sampling of
stack particulate emission. Different particulate size
analyzer namely centrifugal dust classifier, image analyzer,
laser based Melvern master particle sizer, etc. are commonly
used for determination of particle size distribution.
Since finer particulates get deposited on the filter paper,
it is very difficult to remove finer particulates from
filter paper which leads to erroneous results. Image analyzer
is a better choice for particle size analysis of flue
gas in comparison to other analyzer. |
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| 4. |
How are the roles of Green Bench and Appellate
Authority different from each other? |
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In view of growing number of public litigations on environment,
the Supreme Court had suggested all the High Courts in
the country to set up a Green Bench to deal with environment
related litigations at the respective state. This was
done mainly to reduce the increasing burden on the Supreme
Court so that decisions can be taken at the local level.
Appellate Authority is an independent body, which was
formed under the a Parliament resolution to look into
the environmental related matters and advise the Government
on matters pertaining to policy, planning and enforcement
with regard to environment. It is located at the Centre.
There is no direct connection between Green Bench and
Appellate Authority.
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