2. In short, there is very little difference between Pollution and
Contamination, especially in environmental terms.
Pollution can be considered to be something which is not
welcomed in the environment. Contamination is more often
used to refer to a substance which has been introduced to
another substance, generally giving an adverse affect.
Pollution clean-up / remediation of soils or water would involve
exactly the same actions as Contamination clean-up /
remediation.
3. Land can become
contaminated and be
rendered unusable. Land can
get contaminated due to
pollution and contaminants
from surface water,
chemicals, waste water and
other reasons.
4. The main objective of any
land remediation is to
purify the soil and revitalize
it for its intended use, or to
prevent the contamination
from affecting the
environment and human,
animal and plant life.
More info on:
http://adgconsulting.com.au/services/contaminated-land-assessment-remediation.php
5. Before undertaking any remediation of
contaminated land, the first requirement is to
assess the extent of the contamination. For this it
is necessary to be aware of the history of the site
and its earlier uses, and its subsequent
developments that have led to the
contamination.
More info on:
http://adgconsulting.com.au/services/contaminated-land-assessment-remediation.php
6. Defined as the introduction of a substance into the
land so that its quality and function are adversely
affected.
7. Chronic exposure to chromium, lead and other metals,
petroleum, solvents, and many pesticide and herbicide
formulations can be carcinogenic.
Chronic exposure to benzene at sufficient concentrations is
known to be associated with higher incidence of leukemia.
Organophosphates and carbonates can induce a chain of
responses leading to neuromuscular blockage.
Mercury linked to higher incidences of kidney damage.
8.
9. • Remediation technologies are many and varied but can be
categorized into ex-situ and in-situ methods.
• The more traditional remediation approach consists primarily
of soil excavation(disposal to landfill “dig and dump”)
and groundwater(pump and treat).
Remediation techniques for contaminated lands depends upon:
1) Soil characteristics
2) Contaminants characteristics
3) Legal & social requirements
10. Excavation processes can be as simple as hauling
the contaminated soil to a regulated landfill.
11. The soil may be washed Insitu to remove the contaminants.
A leaching agent may be added to water & a pressure gradient is
maintained.
Water for washing is allowed to enter the soil by constructing
horizontal galleries or boreholes.
The leachate is then intercepted or pumped out for treatment.
This technique is good. For non-halogenated volatile org. with
good soil permeability but not suitable for clays.
In the exsitu method, the excavated soil is removed & washed in
a container.
The water may enter from the top & collected at the bottom for
its treatment before it is finally disposed off.
12.
13. In this method air flow is generated through a well
creating press gradient. The air removes volatile
components from the vadose zone. This technique is
especially good for halogenated, volatile & fuel HCs.
This tech is not suitable if air permeability is low or
when carbon content is high or temp is low.
14.
15. i) Incineration: thermal treatment is especially suitable for remediation of
contaminants in the vadose zone. The soil may be excavated & heated at high
temp in the presence of O2. i.e., at 1000-1500 oC. The org are destroyed & the
volatile fraction is removed. Good for halogenated & non-halogenated as well
HCs.
ii) Thermal desorption: in this process the excavated soil is subjected to a low
temp & the volatiles are collected for separate treatment. At high temp
halogenated volatiles & HCs are destroyed.
iii)Vitrification: heat is applied to the contaminated soil causing a melt which
moves downward. It mobilizes the org. & destroy the volatiles. For Insitu
Vitrification large graphite electrodes are inserted in the soil in a grid pattern
(10X10m). a high electric current is applied, soil is cooled. Material is inert.
Long term stability. Consumes large electricity.
16. • Stabilization - involves the addition of reagents to a
contaminated material (e.g. soil or sludge) to produce
more chemically stable constituents.
• Solidification - involves addition of reagents to
impart stability to contain contaminants in a solid
product and reduce access by external agents (e.g. air,
rainfall).
17. Pump and treat involves pumping out contaminated groundwater with
the use of a submersible or vacuum pump and then treating it.
• For petroleum-contaminated sites this material is usually activated
carbon in granular form. It is expensive and a very slow process.
• Other methods include trying to increase the dissolved oxygen
content of the groundwater to support microbial degradation of the
compound.
18.
19. • Despite the absence of a concise regulatory framework to
deal with polluted sites in India, PILs have given the
judiciary enormous scope for intervening in
environmental matters and passing severe penalties
against companies that have been found guilty.
• As for the technologies for remediation, they are expensive
but need to be done for the environmental health and
safety.
20. 1. Mary Harris, Judith Lowe, Phil Crowcroft & Casella
Stanger, “Contaminated land report, Model Procedures for
Management of Land Contamination”, 2008
2. The Water Act (Prevention and Control of Pollution) 1974
3. Hazardous Wastes (Management & Handling)
Amendment Rules, 2003
4. Ravi Costa and Sanjay Sampath, “India: Environmental
Liability and Contamination Regulations”, EHS Journal,
2011
5. Snyder C., "The dirty work of promoting "recycling" of
America's sewage sludge“, Int J Occup Environ Health,
Issue(4)(2005), 415–427
