2. The term of bioremediation has been made of two parts: “bios” means life and refers to
living organisms and “to remediate” that means to solve a problem.
“Bioremediate” means to use biological organisms to solve an environmental problem such
as contaminated soil or groundwater. Bioremediation is the use of living microorganisms to
degrade environmental pollutants or to prevent pollution
BIOREMADIATION
3.
4. Types of Degradation:
based on the principle of degradation, bioremediation is of two types;
A. Biotransformation: Altera
ti
on of the chemical structure of a compound by enzyme s
produced by microorganisms such that new compounds are formed
In the biotransformation process, various organic components are partially degraded,
and the remaining portion is transformed into various other organic matters.
B. Biomineralization
Biomineralization is another type of bioremediation where microorganisms digest
and convert organic waste nutrients into inorganic materials like water, carbon
dioxide, etc.
5. • bioremediation process is a complex system of several factors
(A) Biotic or biological factors-The major biological factors are included enzyme
activity, interaction (competition, succession, and predation), mutation, horizontal
gene transfer, its growth for biomass production, population size and its composition
(B) Abiotic or environmental factors
-the chemical nature and concentration of pollutants, chemical structure, type,
solubility and toxicity.
-the physicochemical characteristics of the environment,- temperature, pH, moisture,
soil structure, water solubility, nutrients, site conditions, oxygen content and redox
potential
6. Most bioremediation systems operate under aerobic conditions; however, anaerobic
conditions are also applicable, thus enabling the degradation of recalcitrant molecules by
using speci
fi
c microorganisms.
• There are groups of microbes which are used in bioremediation such as:
• Aerobic: aerobic bacteria have degrada
ti
ve capaci
ti
es to degrade the complex compounds
such as Pseudomonas, Acinetobacter, Sphingomonas, Nocardia, Flavobacterium, Rhodococcus,
and Mycobacterium.
• These microbes degrade pes
ti
cides, hydrocarbons, alkanes, and polyaroma
ti
c compounds.
Many of these bacteria use the contaminants as carbon and energy source.
•
9. The advantage of bioremediation
• It is a natural process; as an adequate waste treatment process for contaminated material such as soil. Microbes able to
degrade the contaminant, the biodegradative populations become reduced.
• The treatment products are commonly harmless including cell biomass, water and carbon dioxide.
• It needs a very less effort and can commonly carry out on site, regularly without disturbing normal microbial activities.
• This also eradicates the transport amount of waste off site and the possible threats to human health and the environment.
• It is functional in a cost effective process as comparison to other conventional methods that are used for clean-up of toxic
hazardous waste regularly for the treatment of oil contaminated sites.
• It also supports in complete degradation of the pollutants; many of the toxic hazardous compounds can be transformed to
less harmful products and disposal of contaminated material.
• It does not use any dangerous chemicals. Nutrients especially fertilizers added to make active and fast microbial
growth.
• Simple, less labor intensive and cheap due to their natural role in the environment.
• Contaminants are destroyed, not simply transferred to different environmental.
• , possibly allowing for continued site use.
• Current way of remediating environment from large contaminates and acts as ecofriendly sustainable opportunities.
10. Disadvantages or limitations
• it is limited only to those compounds that are biodegradable. Not all compounds are disposed to quick and complete degradation
process
• There are also increasing concerns that the bioremediation products may be more persistent or hazardous than the parent compounds.
For example, trichloroethylene (TCE) is converted to vinyl chloride, a known carcinogen, via a series of biological reactions, resulting in
a sequencing removal of chlorine atoms.
• the effectiveness of bioremediation is highly susceptible to the microbial growth and other environmental parameters of the site.
• Time taking process - bioremediation often requires more time than other treatment options, such as incineration, or excavation and
removal of soil.
• Chances of Secondary pollution- There are particular new products of biodegradation may be more toxic than the initial compounds
and persist in environment.
• Speci
fi
city - Biological processes are highly speci
fi
c, ecofriendly which includes the presence of metabolically active microbial
populations, suitable environmental growth conditions and availability of nutrients and contaminants.
• Technological advancement - Research is needed to develop and engineer bioremediation technologies that are appropriate for sites
with complex mixtures of contaminants that are not evenly dispersed in the environment.
• Scale up limitation- It is dif
fi
cult to scale up bioremediation process from batch and pilot scale studies applicable to large scale
fi
eld
operations
• Regulatory uncertainty- We are not certain to say that remediation is
1
0
0
% completed, as there is no accepted de
fi
nition of clean. Due
to that performance evaluation of bioremediation is dif
fi
cult, and there is no acceptable endpoint for bioremediation treatments.
11. TYPES OF BIOREMADIATION
the basis of place where wastes are removed, there are principally two ways
of bioremediation
In Situ Bioreme
di
atio
n
Ex Situ Bioreme
di
ations
12. IN SITU BIOREMADIATION
in situ bioremediation is applied to eliminate the pollutants in It is a superior
method for the cleaning of soil and ground water
contaminated environments because it saves transportation costs and uses
harmless microorganisms to eliminate the chemical contaminations.
These microorganisms are better to be of positive chemotactic affinity toward
contaminants
This would be of much relevance either where the least investment and pollution
are favored (for example in factories) or in areas contaminated with dangerous
contaminants (for example in areas contaminated with chemical or radioactive
materials)
13. Two types of in situ bioremediation are distinguished based on the origin of the
microorganisms applied as
(i) Intrinsic bioremediation—This type of in situ bioremediation is carried out
without direct microbial amendment and through intermediation in ecological
conditions of the contaminated region and naturally existing
microfauna by improving nutritional and ventilation conditions.
(ii) Engineered in situ bioremediation—This type of bioremediation is performed
through the introduction of certain microorgansims to a contamination site.
As the conditions of contamination sites are most often unfavorable for the establishment and
bioactivity of the exogenously amended microorganisms,
the environment is modified in away so that improved physico-chemical conditions are
provided.
Oxygen, electron acceptors, and nutrients (for example nitrogen and phosphorus) are required
to enhance microbial growth
14. The process of bioremediation here takes place somewhere out from contaminationsite, and
therefore requires transportation of contaminated soil or pumping of groundwater to the site
of bioremediation.
This technique has more disadvantages than advantages.
Depending on the state of the contaminant in the step of bioremediation, ex situ
bioremediation is classified as:
(i) Solid phase system (including land treatment and soil piles)—The system is used in
order to bioremediate organic wastes and domestic and industrial wastes, sewage sludge,
and municipal solid wastes. Solid-phase soil bioremediation including land-farming, soil
biopiling, and composting.
(ii) Slurry phase systems (including solid–liquid suspensions in bioreactors)—
Slurry phase bioremediation is a relatively more rapid process compared to
the other treatment processes
EX SITU BIOREMADIATION
15. Contaminated soil is mixed with water and other additives in a large tank called a
bioreactor and intermingled to bring the indigenous microorganisms in close
contact with soil contaminants.
Nutrients and oxygen are amended, and the conditions in the bioreactor are so
adjusted that an optimal environment for microbial bioremediation is provided.
After completion of the process, the water is removed, and the solid wastes are
disposed off or processed more to decontaminate remaining pollutants
16. in situ technique
Bioaugmentation
Bioaugmentation is the addition of non-native microorganisms that have the
ability to degrade the contaminants that are recalcitrant to the indigenous
microbiota
. Bioaugmentation has been proven successful in cleaning organic pollutant,
but still faces many environmental problems, such as the survival of strains
introduced to soil
.The number of introduced microorganisms usually decreases shortly after
soil soil inoculation.
17. • .
• Bioaugmentation is the introduction of a group of natural microbial strains or a
genetically engineered strain to treat contaminated soil or water.
• Most commonly, it is used in municipal waste water treatment to restart activated
sludge bioreactors.
• At sites where soil and ground water are contaminated with chlorinated ethanes,
such as tetrachloroethylene and trichloroethylene, bioaugmentation is used to
ensure that the in situ microorganisms can completely degrade these
contaminants to ethylene and chloride, which are nontoxic in nature.
18. The success of bioaugmentation strongly depends on the ability of
inoculants to survive in contaminated soil, which may vary due to predation
and an environment that does provide all the conditions and nutrients that
the organism needs to survive.
In some cases the environment may be toxic to the added organism.
19. biosluping
The biological processes in the term "bioslurping" refer to aerobic biological
degradation of the hydrocarbons when air is introduced into the unsaturated
zone.
Bioslurping combines elements of bioventing and vacuum-enhanced
pumping of free-product to recover free-product from the groundwater and
soil, and to bioremediate soils.
The bioslurper system uses a "slurp" tube that extends into the free-product
layer.
20. Much like a straw in a glass draws liquid, the pump draws liquid (including
free-product) and soil gas up the tube in the same process stream.
Pumping lifts light non-aqueous phase liquids LNAPL such as oil, off the top
of the water table and from the capillary fringe (i.e., an area just above
the saturated zone, where water is held in place by capillary forces).
The LNAPL is brought to the surface, where it is separated from water and air.
21. LIMITATION
less effective in tight (low-permeability) soils
greatest limitation to air permeability is excessive soil moisture. .
Too much moisture can reduce air permeability of the soil and decrease its
oxygen transfer capability.
Too little moisture will inhibit microbial activity.
slow process
22. application
Bioslurping is used to remediate soils contaminated by fuel, as well as
groundwater contaminated with fuel LNAPLs
. It can help to remediate soils contaminated with nonnhalogenated volatile
organic compounds (VOCs) and semi-volatile organic compounds (SVOCs).
23. injection of air under pressure below the
water table to increase ground water o
2
concentration .
and enhance the rate of biological
degradation of contaminants by naturally
occurring bacteria
biosparging
24. Components Of A Biosparging System
A typical biosparging system design includes the following components
Sparging well orientation, placement, and construction details
Manifold piping
Compressed air equipment
Monitoring and control equipment A nutrient delivery system is sometimes included
in biosparging design.
If nutrients are added, the design should specify the type of nutrient addition and
the construction details
25. Biosparging should not be used if the following site conditions exist:
Free product is present-Biosparging can create groundwater mounding which could
cause free product to migrate and contamination to spread.
Basements, sewers, or other subsurface con
fi
ned spaces are located near the site.
Potentially dangerous constituent concentrations could accumulate in basements and
other subsurface con
fi
ned spaces unless a vapor extraction system is used to control
vapor migration.
The effectiveness of biosparging depends primarily on two factors:
The permeability of the soil which determines the rate at which oxygen can be supplied
to the hydrocarbon-degrading microorganisms in the subsurface.
The biodegradability of the contaminant constituents which determines both the rate at
which and the degree to which the constituents will be degraded by microorganisms.
26.
27. natural attenuation
Natural attenuation and bioremediation are methods to treat polluted
environments, in which microorganisms contribute to pollutant degradation.
Essentially an in situ biological remediation as the nutrients, moisture content,
temperature and oxygen can all occur naturally within the ground.
These native microorganisms would simply reproduce by themselves and reduce
the concentration of contamination in the appropriate environment...
28. • USES
• VOCs, SVOCs and fuel hydrocarbons are commonly evaluated for natural
attenuation.
• Some pesticides also can be allowed to naturally attenuate - but generally less
effective.
29. ADVANTEGE
Less generation & transfer of waste.
Less intrusive (only ground monitoring
wells required).
May be applied to part/or all of a
contaminated area (depending on site
conditions, cleanup objectives and
allowable treatment time)
Generally lower cost than active
remediation -
DISADVANTAGE
The process may be too slow
Toxicity of contaminant may be too
great.
Long term, more extensive
performance monitoring reqd.
Longer time to achieve clean-up
objectives.Typically requires several
years.
Site characterisation (modelling/
evaluation) may be more complex and
costly.
30. bioventing
• Bioventing is a promising new technology that stimulates the natural in situ biodegradation of any aerobically
degradable compounds
• Bioventing is involves stimulating indigenous microorganisms through the addition of a gas (typically air) using
extraction or injection wells to degrade organic contaminants (typically petroleum hydrocarbons) present in
unsaturated soil.
• Air most often is injected into the unsaturated vadose zone, but at some sites, can be extracted from the vadose zone.
• It uses low air
fl
ow rates to provide only enough oxygen to sustain microbial activity, that also minimizes the
volatilization and release of contaminants to the atmosphere.
• Oxygen is most commonly supplied through direct air injection into residual contamination in soil by means of wells.
• Bioventing primarily assists in the degradation of adsorbed fuel residuals, but also assists in the degradation
of volatile organic compounds (VOCs) as vapors move slowly through biologically active soil.
• Bioventing can be classi
fi
ed into ac
ti
ve or passive technology. In passive technology the gas exchange through the vent
wells occurs only by the effect of atmospheric pressure, whereas in active technology the air is driven into the ground
with the aid of a blower or a pump.
31.
32. types of bioventing
active bioventing
passive bioventing.
anaerobic bioventin
Natural Pressure-Driven Bioventing
Cometabolic Bioventing
33. The most common bioventing approach is to
use one or more blowers to introduce air into
the vadose zone (referred to as active
bioventing).
The blowers can be operated to either inject air
or extract soil vapors from a series of vent wells
.When extracting vapors, removal of the gas
creates a negative pressure that causes
atmospheric air to be drawn into the
subsurface.
34. Less common is the use of passive
bioventing systems in which
changes in atmospheric pressure
and, in rare situations (e.g., sites
where tidal
fl
uctuations are
pronounced) changes in
groundwater levels facilitate the
introduction of ambient air into the
vadose zone
.Vent wells equipped with
specially-designed valves that allow
fresh air to enter the well during
high pressure conditions are used
to facilitate the exchange of gases.
35. bio stimulation
This method involves the addition of nutrients to a polluted site in order to
encourage the growth of naturally occurring chemical-degrading microorganisms
. Biostimulation is primarily done by the addition of various nutrients that are
limited in the soil as well as electron acceptors, such as phosphorus, nitrogen and
oxygen, or increasing the amount of available carbon in order to increase the
population or activity of naturally occurring microorganisms.
Other approaches are to optimize environmental conditions such as aeration, the
addition of nutrients, altering pH and temperature control
.The primary advantage of biostimulation is that it is done by native microorganisms
that are well-suited to the environment, and are already well distributed spatially.
The challenge is delivering additives so they are readily available to the subsurface
microbes.
36. ex into( solid phase )
Biopiling
Excavated soils are mixed with soil amendments and placed on a treatment area.
Biopiles are aerated with the use of perforated pipes and blowers in order to control
the progression of biodegradation more ef
fi
ciently by controlling the supply of
oxygen , which in turn may affect other factors such as pH.
This system is primarily used to remediate systems with oil and hydrocarbon
contamination.
The remediated soil is placed in a liner to prevent further contamination of the soil,
they may also be covered with plastic to control runoff, evaporation,
and volatilization.
37.
38.
39. composting
Nutrients are added to soil that is mixed to increase aeration and activation of
indigenous microorganisms.
Composting is done in a separate container, then when composting is complete it is
incorporated into the soil.
Bioremediation by the utilization of compost relies on the adsorption capabilities of
organic matter and the degradation capabilities of microorganisms present
Composting is recognized as as one of the most cost-effective technologies for soil
bioremediation and it can be done on large and small scales.
The use of composting is a very versatile technique for soil polluted by a wide range
of organic pollutants and heavy metals, making it great for easier remediation
involving various pollutants.
40. The utilization of organic wastes for soil remediation is also helpful in decreasing
the need for their storage and treatment.
Organic matter that is generated from composting offers the bene
fi
t of improving
soil quality and structure.
Composting is primarily used for remediation over a longer period of time, as the
nutrients for the microbes are released gradually and requrire more time compared
to quicker treatments such as biostimulation.
41.
42. Contaminated soil is mixed with amendments such as nutrients, and then they are
tilled into the earth, or the contaminated soil is applied into lined beds and
periodically turned over or tilled to aerate the waste.
The topmost layer is the area of concentration for this method, so it is not ideal for
deeper remediation.
Land farming differs from composting because it actually incorporates contaminated
soil into soil that is uncontaminated .
The higher zone of remediation will typically contain primarily lighter hydrocarbons
that can be volatilized.
The material is periodically tilled for aeration to hasten remediation of any nutrients
and allow more oxygen to act as electron acceptors, as well as allowing volatilization to
occur.
land farming
43. Contaminants are degraded, transformed, and immobilized by microbiological
processes and oxidation.
Soil conditions are controlled to optimize the rate of contaminant degradation,
moisture content, frequency of aeration, and pH are all conditions that may be
controlled
44.
45. bio
fi
ltration
Air is polluted by a variety of volatile organic compounds created by a range of
industrial processes.
While chemical scrubbing has been used to clean gases emitted from chimneys,
the newer technique of ‘bio
fi
ltration’ is helping to clean industrial gases.
This method involves passing polluted air over a replaceable culture medium
containing microorganisms that degrade contaminates into products such as
carbon dioxide, water or salts.
Bio
fi
ltration is the only biological technique currently available to remediate
airborne pollutants.
46. Bio
fi
ltration is a process, in which, microorganisms supported on inert materials
are used to degrade organic pollutants for air, gas and water
bioremediationTypes of bio
fi
lters:
1
- Bioscrubbers.
2
- Biotrickling
fi
lters.
3
- Slow sand or carbon
fi
lters.
48. Slow sand or carbon
fi
lters
Slow sand or carbon
fi
lters work through the formation of a gelatinous layer (or
bio
fi
lm layer) on the top few millimetres of the
fi
ne sand or carbon layer.
This layer contains bacteria, fungi, protozoa, rotifera and a range of aquatic insect
larvae (i.e. rotifers).
49. .A slurry bioreactor may be defined as a containment vessel and apparatus
used to create a three-phase (solid, liquid, and gas) mixing condition to increase the
bioremediation rate of soil-bound and water-soluble pollutants as a water slurry of
the materials contaminated with petroleum residueS
slurry phase -bioreactor
50. • The excavated soil is physically pre-treated to separate stones and rubble. In
some cases, it is also pre-washed to concentrate the contaminants into a smaller
volume of soil.
• An aqueous slurry is created by combining the contaminated soil, sediment, or
sludge with water and nutrients - amount depends altering the concentration for
an apt rate of bio-degradation to occur. (Typically, the slurry contains from
1
0
to
3
0
% solids by weight).
• This is then placed into a bio-reactor The slurry is mixed to keep solids
suspended and microorganisms in contact with the soil contaminants.
• Upon completion of the process, the slurry is dewatered and the treated soil can
be replaced to it's position. Only the contaminated
fi
nes & collected wastewater
require further treatment.
51. If necessary, an acid or alkali may be added to control pH.
Microorganisms also may be added if a suitable population is not present.
Dewatering devices that may be used include clari
fi
ers, pressure
fi
lters,
vacuum
fi
lters, sand drying beds, or centrifuges.
Slurry-phase bioreactors may be classi
fi
ed as short- to medium-term
technologies.
52. Treats solid phases contaminated by non-halogenated and , explosives, petroleum
hydrocarbons, petrochemicals, solvents, some pesticides, wood preservatives & other
organic chemicals.
The ability to add specially adapted microorganisms allow treatment of halogenated
VOCs and SVOCs, pesticides, and PCBs. (e.g. otherwise more persistent compounds).
53. Limitations/Disadvantages:
• Must excavate & transport the contaminated media (unless lagoon implementation).
• Bio-reactor design can be dif
fi
cult and expensive.
• Nonhomogeneous or clayey soils can create serious material handling problems.
• Dewatering soil
fi
nes after treatment can be expensive.
• An acceptable method for disposing/further treating waste-water is required.
• A preliminary treatability study should be conducted.
54. PHYTOREMADIATION
1. Phytostabilization.In this process, chemical compounds produced by the plant immobilize contaminants, rather than degrade them.
2. Phytoaccumulation (also called phytoextraction). In this process, plant roots absorb the contaminants along with other nutrients
and water.The contaminant mass is not destroyed but ends up in the plant shoots and leaves.This method is used primarily for
wastes containing metals.
3. Hydroponic Systems for Treating Water Streams (Rhizo
fi
ltration). Rhizo
fi
ltration is similar to phytoaccumulation, but the plants
used for cleanup are raised in greenhouses with their roots in water.This method of growing can be used for ex-situ groundwater
treatment.That is, groundwater is pumped to the surface to irrigate these plants.Typically hydroponic systems utilize an arti
fi
cial
soil medium, such as sand mixed with perlite or vermiculite. As the roots become saturated with contaminants, they are harvested
and disposed of.
4. Phytovolatilization.In this process, plants take up water containing organic contaminants and release the contaminants into the air
through their leaves.
5. Phytdegradation. In this process, plants actually metabolize and destroy contaminants within plant tissues.
6. Hydraulic Control. In this process, trees indirectly remediate by controlling the groundwater movement.Trees act as natural pumps
when their roots reach down towards the water table and establish a dense root mass that takes up large quantities of water. A
poplar tree, for example, pulls out of the ground
3
0
gallons of water per day, and cottonwood can absorb up to
3
5
0
gallons per day.
55.
56. u Approximately
4
0
0
plant species have been classi
fi
ed as hyperaccumulators of
heavy metals, such as grasses, sun
fl
ower, corn, hemp,
fl
ax, alfalfa, tobacco, willow,
Indian mustard, poplar, water hyacinth, etc.
57. mycoremadiation
A wide number of fungal species have shown incredible abilities to degrade a growing
list of persistent and toxic industrial waste products and chemical contaminants to less
toxic form or non-toxic form
. Mycelium reduces toxins by different enzymatic mechanism to restore the natural
fl
ora
and fauna.
White rot fungi has successfully been utilized in degradation of environmental
pollutant like polyaromatic compounds, pesticides etc.
The present review gives a insights on degradation aspects of heavy metals, PAH
especially using different fungal species.
58. White rot fungi has potential to degrade contaminants using wide range of enzymes.
Mycoremediation is promising alternative to replace or supplement present treatment
processes
Mushrooms are vegetal organisms with the ability to accumulate heavy metals.This
ability is explained by the presence of a rich network of hyphae which occurs in a
considerable volume in the upper layer of soil.
This allows mushrooms to collect required water and minerals from the soil for
production of fruiting body
Every species of mushroom has a speci
fi
c capacity, genetically controlled for absorption
of one or another heavy metal from the soil
. Mushroom can be successfully utilized in mycoremediation technologies, where their
feature concerning the uptake of heavy metal is bene
fi
cial
59. mycoremediate heavy metals which include
Pleurotus platypus,
Agaricus bisporus,
Calocybe indica,
Hygrophorus etc.
