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DEPARTMENT OF CIVIL ENGINEERING
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LAND
RECLAMATION
(REMEDIATION TECHNIQUES)
PRESENTED BY:
HILAL BASHIR
M TECH 1ST YEAR
32212101
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contents
 Introduction
 Identifying Contamination
 Risk assessment
 Remediation methods for contaminated sites
 Conclusive remarks
 References
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Introduction
 Approximately 90.00% of the world’s population depends directly or
indirectly on land.
 The degradation of land or simply land degradation is one of the
foremost challenging issues most of which is a consequence of
man’s continuous or incessant exploration.
 The Department of the Environment (UK) has described
contaminated land as ‘land which represents an actual or potential
hazard to health or the environment as a result of current or previous
use’.
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Identifying contamination.
 Contamination can create a range of hazards, depending on its
composition and nature. It may be present in solid, liquid or gas
phases, and may be physical, chemical or biological.so we need to
identify the contamination first.
 As Contamination may be hazards to:
• People
• Water resources
• Flora and fauna
• Foundations and structures
 The process of assessing whether the existence of contamination
matters is termed as risk assessment. This is discussed more fully in the
next section.
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Risk assessment.
 The process of risk assessment can be defined as simply ‘an
evaluation of the probability of harm and, in the context of
contaminated land, is concerned with gathering and interpreting
information on the characteristics of sources, pathways and
receptors at a specific site and understanding the uncertainties
inherent to ensuring assessment of risk.
 The process of risk assessment can be viewed as consisting of four
key stages:
• hazard identification
• exposure assessment (what are the key environmental pathways and exposure routes
by which the toxic substances can reach the receptors)
• dose—response assessment (how potent are the toxic substances that can reach the
receptor).
• risk characterization (what level of risk can be assigned to each source—pathway—
receptor linkage).
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Remediation methods for
contaminated sites.
 Soil remediation is the application of proven technologies to
mitigate and manage risks from contaminated soils that could be
harmful to human health and the environment.
 In Remediation techniques, either the land is fully recovered from
contamination or the contamination is minimized to make the land
useful for different purposes.
 Soil remediation falls into three primary categories: In-situ, ex-situ and
other treatment. Under each category is a range of specialized
technology and methods that may be required for any given
project.
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Different methods of soil remediation.
1. Physical and
chemical
remediation.
• Solidification and
stabilization.
• Removal to landfill.
• Washing and
sorting treatments.
• Chemical oxidation
2. Thermal soil
remediation.
• Steam Enhanced
Extraction (SEE).
• Electrical
Resistance Heating
(ERH).
• Thermal
Conduction
Heating (TCH).
3. Bio
Remediation.
• Intrinsic
Bioremediation.
• Projected
Bioremediation.
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Bio Remediation:
 Bioremediation is the process by which living beings such as plants,
algae and microorganisms are used to remediate, reduce or
remove contamination from the environment.
 Bioremediation of soil uses living organisms to degrade the soil. In
essence, the biological activity removes or immobilizes soil
pollutants.
 Most bioremediation projects require months or even years to
complete the treatment process.
 Costs related to biological remediation are generally lower than
other techniques.
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A). In situ Bioremediation:
✓ Permeable Reactive Barriers (PRBs):
• A permanent or semi-permanent reactive barrier composed mainly
of iron immersed in the contaminated groundwater stream.
• Remediate groundwater contaminated by many types of pollutants
such as chlorinated hydrocarbons and heavy metals.
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✓ Bio slurping:
• Remediation of
groundwater and
soil by indirect
O2 supply and
improve pollutant
degradation.
• Bio slurping is
unsuitable to
treat low
permeable soils.
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✓ Bioventing:
• Bioventing involves controlled stimulation of the air flow, providing oxygen
to increase microbial activity and, consequently, enhance bioremediation.
• This technique has been used successfully in the remediation of soils
polluted by oil products.
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✓ Biosparging:
• In bio sparging, air is introduced into the soil to promote the
degradation capacity of microorganisms. In contrast to bioventing,
air is introduced inside the saturated area, causing the upward
movement of volatile pollutants.
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✓ Phytoremediation:
• Phytoremediation refers to the use of plants in polluted sites to promote biological,
biochemical, physical, microbiological and chemical interactions to attenuate the
toxicity of contaminants.
• Elemental contaminants like heavy metals or radioactive elements are mainly
extracted, transformed and sequestered, while organic contaminants are eliminated
mainly through rhizodegradation, biodegradation, vaporization or stabilization.
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B). Ex situ bioremediation:
 The polluted material is removed and degraded in special facilities
outside the incident site.
 The selection of an ex-situ bioremediation technique is usually made
on the basis of the following aspects:
• Operating costs
• Extent and depth of contamination
• Type of contaminant
• Location and geological features of the contaminated site.
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Ex situ techniques:
 Bioreactors: Contaminants are kept in a containment container where, using
various types of devices to mix the sludge, a mixture (solid, liquid, gas) is obtained.
The biofilm formed stimulates the biodegradation of pollutants and increase the
biomass level.
 Bio piles: Bioremediation through bio piles consists in the piling of contaminated soil
and subsequent aeration to promote biodegradation mainly by improving microbial
activity.
 Compositing: Composting is an ex-situ aerobic process by which organic waste is
decomposed by thermophilic biological agents to obtain a humic amendment
known as composit, which is used as soil fertilizer.
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C). Surface enhanced soil bioremediation:
 The use of surfactants and bio surfactants may be an efficient
option to assist soil treatment.
✓ Synthetic surfactants: Synthetic surfactants include ionic and non-ionic
surfactants. Both have been used successfully to remove different types of toxic
organic compounds as well as heavy metals contaminating the soil.
✓ Biosurfactants: Biological counterpart of synthetic surfactants
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Conclusive Remarks:
 The primary aims of remediation of a contaminated site are either
the reduction of actual or potential environmental threat, or the
reduction of potential risks that are unacceptable to levels that are
acceptable.
 Identifying the most appropriate remediation method is of prime
importance to reduce or remove the threat associated with the
contaminants.
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References:
 L. D. Hooper, F. W. Oehme and G. R. Krieger, in Hazardous Materials Toxicology, ed. J. B. Sullivan,
Jr., and G. R. Kreiger, Williams and Wilkins, Baltimore, 1992
 Department of the Environment (DoE), A Framework for Assessing the Impact of Contaminated
Land on Groundwater and Surface Water, CLR1, DoE, London, 1994, vols. 1 and 2.
 S. J. T. Pollard, D. O. Harrop, P. Crowcroft, S. H. Mallett, S. R. Jeffries and P. J. Young, J. Chart. Inst.
Water Environ. Manage., 1995.
 Martin and P. Bardos, A Review of Full Scale Treatment Technologies for the Remediation of
Contaminated Soil, BPP Publications, Richmond, 1996.
 Davis, E.L., 1997. How Heat Can Accelerate In-situ Soil and Aquifer Remediation: Important
Chemical Properties and Guidance on Choosing the Appropriate Technique. US EPA Issue Paper,
EPA/540/S-97/502.
 Derby (2009). "In Situ Chemical Oxidation for Groundwater Remediation." SERDP/ESTCP
Environmental Remediation Technology (2011). Environment. Groundwater and Environmental
Services, Inc., Web.
 Banerjee, A.; Roy, A.; Dutta, S.; Mondal, S. Bioremediation of hydrocarbon—A review. Int. J. Adv.
Res. 2016.
 Saxena, G.; Bharagava, R.N. Bioremediation of Industrial Waste for Environmental Safety: Volume
I: Industrial Waste and Its Management; Saxena, G., Bharagava, R.N., Eds.; Springer: Singapore,
2020.
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THANK YOU
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