Phytostabilization

1. PHYTOSTABILIZATION AND TYPES
PRESENTED BY
VIVEKANANDHAARTS AND SCIENCE COLLEGE FOR WOMEN
Veerachipalayam - 637 303, Sankagiri, Salem Dt., TamilNadu, India.
(Affiliated to Periyar University, Salem ; Recognised Under Section 2(f) & 12(B) of the UGC Act, 1956 )
GUIDE BY
Dr.R. DINESH KUMAR
Assistant Professor of Microbiology
Vivekanandha Arts and Science College for Women
M.SANGEETHA
I- MSc.,Microbiology
Vivekanandha Arts and Science College for Women
DEPARTMENT OF MICROBIOLOGY
SUBJECT: BIOREMEDIATION

2. PHYTOSTABILIZATION:
• Phytostabilization involves the establishment of a plant cover on the
surface of the contaminated sites with the aim of reducing the mobility
of contaminantswithin the vadose zone through accumulation by roots
or immobilization withinthe rhizosphere, thereby reducing off-site
contamination.
• The process includestranspiration and root growth that immobilizes
contaminants by reducing leaching, controlling erosion, creating an
aerobic environment in the root zone, andadding organic matter to the
substrate that binds the contaminant
• Critically examine the applicability of this technology tomanage
metal(loid)s contaminated soils and identify fertile areas for
futureresearch.

3. TYPES OF PHYTOSTABILIZATION :
• The mechanism of phytovolatilization occurs in two forms as direct
phytovolatilization and indirect phytovolatilization.
• Phytoremediation techniques: 1) rhizofiltration, a water remediation
technique involving the uptake of contaminants by plant roots; 2)
phytoextraction, a soil technique involving uptake from soil, 3)
phytotransformation, applicable to both soil and water, involving the
degradation.
• Phytovolatilization involves the uptake of contaminants by plant roots
and its conversion to a gaseous state, and release into the atmosphere.

4. PHYTOSTABILIZATION PROCESS :

5. • Phytostabilization involves the reduction of the mobility of heavy
metals in soil.
• Immobilization of metals can be accomplished by decreasing wind-
blown dust, minimizing soil erosion, and reducing contaminant
solubility or bioavailability to the food chain.
• Phytostimulation (or rhizodegradation) is the enhancement of soil
microbial activity for the degradation of organic contaminants,
typically by organisms that associate with roots.
• Phytovolatilization involves the uptake of contaminants by plant roots
and its conversion to a gaseous state, and release into the atmosphere.
• Helps to reduce air pollution and maintain the normal temperature in
the industrial site.

6. IN SITU PHYTOSTABILIZATION :
• In situ phytoremediation is the onsite contaminant removal through
plant uptake in a cost-effective and eco-friendly way.
• In situ sediment treatment involves applying or mixing of an
amendment into sediments.
• Mixing may be achieved either passively, through natural biological
processes such as bioturbation, or actively through mechanical means
(using augers, for instance).
• Its goal is to promote the use of field-tested phytoremediation methods
for removing soil and water pollutants from agricultural, industrial,
military, and municipal sources.

7. ENGINEERED IN – SITU PHYTOSTABILIZATION TYPES :
1.PHYTOSEQUESTRATION : Also referred to as phytostabilization,
there are many different processes that fall under this category.
• They can involve absorption by roots, adsorption to the surface of
roots, or the production of biochemicals by a plant that is released into
the soil or groundwater.
• In the immediate vicinity of the roots and can sequester, precipitate, or
otherwise, immobilize nearby contaminants.
• It refers to the natural ability of certain plants called
hyperaccumulators to bioaccumulate, degrade, or render harmless
contaminants in soil, water, or air.

8. CONTINUE:
2 RHIZODEGRADATION : This process takes place in the soil or
groundwater immediately surrounding the plant roots.
• Exudates (excretions) from plants stimulate rhizosphere bacteria to
enhance biodegradation of soil contaminants.
• Depending on the concentration of contaminants in the soil,
phytoremediation may be limited to less concentrated areas since
plants are limited in the amount of waste they can uptake and process.
• The effect of various compounds on the entire ecosystem of which
plants may be a part.

9. CONTINUE :
3. PHYTOHYDRAULICS : Use of deep-rooted plants—usually trees—to
contain, sequester, or degrade groundwater contaminants that come
into contact with their roots.
• For example, poplar trees were used to contain a groundwater plume
of methyl-tert-butyl-ether (MTBE).
• Phytoremediation is a cost-effective, plant-based approach to
remediation that takes advantage of the ability of plants to
concentrate elements.
• Phytoremediation has begun to emerge together with biological and
engineering strategies.

10. CONTINUE :
4. PHYTOEXTRACTION : This term is also known as
phytoaccumulation.
• Plants take up or hyper-accumulate contaminants through their roots
and store them in the tissues of stems or leaves.
• The contaminants are not necessarily degraded but are removed from
the environment when the plants are harvested.
• This is particularly useful for removing metals from soil. In some
cases, the metals can be recovered for reuse by incinerating the plants
in a process called phytomining.

11. CONTINUE :
5. PHYTOVOLATILIZARION : Plants take up volatile compounds
through their roots, and transpire the same compounds, or their
metabolites, through the leaves, thereby releasing them into the
atmosphere.
• Contaminants are taken up into the plant tissues where they are
metabolized, or biotransformed.
• Where the transformation takes place depends on the type of plant and
can occur in roots, stems, or leaves.
• Phytoremediation basically refers to the use of plants and associated
soil microbes to reduce the concentrations or toxic effects of
contaminants in the environment.

12. ADVANTAGES OF IN- SITU PHYTOSTABILIZATION :
• In contrast, phytoremediation has the advantages of in-situ
remediation, low cost and environmental friendliness, and is the
preferred solution.
• The main advantages of in situ methods are that they can reduce the
risks of exposure and secondary contamination, minimize the
disturbance of the site, and lower the costs and time of remediation.
• While in situ remediation is more cost effective, the thoroughness of
this method is less effective than the ex situ remediation.
• Help preserve diverse genetic material, preserve natural habitats and
species relationships, and remain as reservoirs of various resources
for humans.

13. DISADVANTAGE OF IN-SITU PHYTOSTABILIZATION :
• It is a natural way to protect animals and plants. Large populations can
be protected at once.
• This is a more discreet method than simply keeping the species away
from their natural setting.
• There is a higher chance of recovery than in situ preservation methods.
• Ex-situ conservation keeps animals and plants safe from external
threats and educates the public about conservation efforts.
• Maintenance of organisms in artificial habitats, deterioration of genetic
diversity, inbreeding depression, adaptations to captivity, and
accumulation of deleterious alleles.

14. SHALID PHASE PHYTOSTABILIZATION :
• According to USEPA (2000), the installation of phytoremediation
technology including phytostabilization is categorized into three
main steps, i.e. Design, Installation and Operation.
• These are the sequential steps which must be followed one by
one.
• Phytostabilization is useful at sites with shallow contamination
and where contamination is relatively low.
• Solid-phase bioremediation is an ex-situ technology in which the
contaminated soil is excavated and placed into piles.
• It is also includes organic waste like leaves, animal manures and
agriculture wastes, domestic, industrial wastes and municipal

15. SLURRY PHASE SYSTEM :
• Biologically there are three types of slurry-phase bioreactors : aerated
lagoons, low-shear airlift reactor, and fluidized-bed soil reactor.
• The first two types are in use of full scale bioremediation, while the
third one is in developmental stage.
• Slurry phase biological treatment comprises of the treatment of
excavated soil in a bioreactor. The soil is initially processed to separate
out any stones and rubble that may be present.
• Slurry reactors are three-phase reactors, meaning they can be used to
react solids, liquids, and gases simultaneously.

17. ADVANTAGES OF EX-SITU PHYTOSTABILIZATION :
• The main advantage of ex situ treatments is that they generally require
shorter time periods.
• The uniformity of treatment because of the ability to screen,
homogenize, and continuously mix the contaminated media; however,
ex situ processes require excavation of soils.
• Ex-situ bioremediation involves the removal of hazardous waste to an
isolated, above-ground area for treatment.
• The process of bioremediation is from this point closely controlled and
monitored by the experts involved, so that it occurs more quickly and
thoroughly.

19. DISADVANTAGE OF EX – SITU PHYTOSTABILIZATION :
• However, ex situ methods also have some disadvantages, such as high
costs, high energy consumption, large volumes of waste, and potential
environmental impacts of transportation and disposal.
• Disadvantages: Phytoremediation simply relocates toxic heavy metals,
it does not remove them from the locale.
• Phytoremediation is limited to the surface area and depth occupied by
the roots. Slow growth and low biomass require a long-term
commitment.
• The disadvantages of in situ conservation are brought about by a lack
of complete control over the many factors which influence the survival
of individuals and therefore the genetic makeup of the conserved
population.