Transcript Document

Bioremediation
Bioremediation ?
• Biology + Remediation = Bioremediation
• Biological organisms (bacteria, fungi,
plant)
• Method used to clean the contaminated
area
• High toxic to less toxic (or) non toxic
Principles
• Microorganisms - take pollutants from the
environment - used to enhance the growth
and metabolic activity
• Bacteria, Fungi are well known for
degrading complex molecules and
transform the product into part of their
metabolism
Definition
• The process whereby organic wastes are
biologically degraded under controlled
conditions to an innocuous state.
• Bioremediation is the use of living
organisms, primarily microorganisms, to
degrade the environmental contaminants
into less toxic forms.
Process
• Microorganisms release enzymes to
breakdown the contaminant into digestible
farm
BIOREMEDIATION
In situ
Ex situ
Bioventing
Land farming
Biosparging
Compost
Biostimulation
Biopiles
Bioaugmentation
Bioreactors
Phytoremediation
Bioventing
The most common in situ treatment
Supplying air and nutrients through wells to
contaminated soil to stimulate the indigenous
bacteria.
Bioventing employs low air flow rates and
provides only the oxygen necessary for the
biodegradation while minimizing volatilization
and release of contaminants to the
atmosphere.
It works for simple hydrocarbons and can be
used where the contamination is deep under
the surface.
Bioventing
Biosparging
• Biosparging involves the injection of air under
pressure below the water table to increase
groundwater oxygen concentrations and
enhance the rate of biological degradation of
contaminants by naturally occurring bacteria.
• Biosparging increases the mixing in the
saturated zone and there by increases the
contact between soil and groundwater.
• Low cost of installing small - diameter air
injection points allows considerable flexibility in
the design and construction of the system.
Biosparging
Biostimulation
• It involves supplying oxygen and nutrients by
circulating aqueous solutions through
contaminated soils to stimulate naturally
occurring bacteria to degrade organic
contaminants.
• It can be used for soil and groundwater.
Generally, this technique includes conditions
such as the infiltration of water - containing
nutrients and oxygen.
Bioaugumentation
• Bioremediation frequently involves the addition of
microorganisms indigenous or exogenous to the
contaminated sites.
• Two factors limit the use of added microbial cultures
in a land treatment unit:
1) nonindigenous cultures rarely compete well enough
with an indigenous population to develop and sustain
useful population levels and
2) most soils with long-term exposure to biodegradable
waste have indigenous microorganisms that are effective
degrades if the land treatment unit is well managed.
Land forming
• It is a simple technique in which contaminated soil
is excavated and spread over a prepared bed and
periodically tilled until pollutants are degraded.
• The goal is to stimulate indigenous
biodegradative microorganisms and facilitate their
aerobic degradation of contaminants.
• In general, the practice is limited to the treatment
of superficial 10–35 cm of soil.
• Since landfarming has the potential to reduce
monitoring and maintenance costs, as well as
clean-up liabilities, it has received much attention
as a disposal alternative.
Composting
• Composting is a technique that involves
combining contaminated soil with
nonhazardous organic amendants such
as manure or agricultural wastes.
• The presence of these organic materials
supports the development of a rich
microbial population and elevated
temperature characteristic of composting.
Biopiles
• Biopiles are a hybrid of landfarming and
composting. Essentially, engineered cells are
constructed as aerated composted piles.
• Typically used for treatment of surface
contamination with petroleum hydrocarbons they
are a refined version of landfarming that tend to
control physical losses of the contaminants by
leaching and volatilization.
• Biopiles provide a favorable environment for
indigenous aerobic and anaerobic
microorganisms.
Bioreactors
• Slurry reactors or aqueous reactors are used for ex
situ treatment of contaminated soil and water pumped
up from a contaminated plume.
• Bioremediation in reactors involves the processing of
contaminated solid material (soil, sediment, sludge) or
water through an engineered containment system.
• 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 contaminated soil
and biomass (usually indigenous microorganisms)
capable of degrading target contaminants.
Phytoremediation
• Plants have been commonly used for the bioremediation process
called Phytoremedation, which is to use plants to decontaminated
soil and water by extracting heavy metals or contaminants.
• Plants that are grown in polluted soil are specialized for the process
of Phytoremedation.
• The plants roots can extract the contaminant, heavy metals, by one
of the two ways, either break the contaminant down in the soil or to
suck the contaminant up, and store it in the stem and leaves of the
plant.
• Usually the plant will be harvest and removed from the site and
burned.
• Phytoremediation process is used to satisfy environmental regulation
and costs less then other alternatives.
• This process is very affective in cleaning polluted soil.
Types
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Phytoextraction
Phytotransformation
Phytostabilisation
Phytodegradation
Rhizofiltration
Phytoextraction
• The plants to accumulate contaminants into the
roots and aboveground shoots or leaves.
• This technique saves tremendous remediation
cost by accumulating low levels of contaminants
from a widespread area.
• Unlike the degradation mechanisms, this process
produces a mass of plants and contaminants
(usually metals) that can be transported for
disposal or recycling.
Phytotransformation
• Refers to the uptake of organic
contaminants from soil, sediments, or
water and, subsequently, their
transformation to more stable, less toxic,
or less mobile form.
• Metal chromium can be reduced from
hexavalent to trivalent chromium, which is
a less mobile and noncarcinogenic form.
Phytostabilization
• The plants reduce the mobility and
migration of contaminated soil.
• Leachable constituents are adsorbed and
bound into the plant structure.
• They form a stable mass of plant from
which the contaminants will not reenter
the environment.
Phytodegradatio
n
• Breakdown of contaminants through the activity
existing in the rhizosphere.
• This activity is due to the presence of proteins and
enzymes produced by the plants or by soil
organisms such as bacteria, yeast and fungi.
• Rhizodegradation is a symbiotic relationship that
has evolved between plants and microbes.
• Plants provide nutrients necessary for the
microbes to thrive, while microbes provide a
healthier soil environment.
Rhizofiltration
• It is a water remediation technique that
involves the uptake of contaminants by
plant roots.
• Rhizofiltration is used to reduce
contamination in natural wetlands and
estuary areas.
Limitations of Bioremediation
• Contaminant type & Concentration
• Environment
• Soil type condition & Proximity of ground
water
• Nature of organism
• Cost benefit ratios : Cost Vs Env. Impact
• Does not apply to all surface
• Length of bioremediation process
Advantages
• Minimal exposure of on site workers to the contaminant
• Long term protection of public health
• The Cheapest of all methods of pollutant removal
• The process can be done on site with a minimum amount of space
and equipment
• Eliminates the need to transport of hazardous material
• Uses natural process
• Transform pollutants instead of simply moving them from one media
to another
• Perform the degradation in an acceptable time frame
DISADVANTAGES
• Cost overrun
• Failure to meet targets
• Poor management
• Climate Issue
• Release of contaminants to environment
• Unable to estimate the length of time it’s going to take, it may
vary from site.
Bacterial genera isolated from
water and sediment samples of different lakes
55 isolates
Screening of nitrate reducers
Nitrate reduction test
Reduction of nitrate / nitrite to ammonium
Appearance of reddish orange colour
Based on intensity of the colour
No reduction : Less reduction : +
Moderate reduction : ++
High reduction : +++
Potent isolates used for study (+++)
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•
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•
•
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Pseudomonas sp. (KW 1)
Pseudomonas sp. (KW 8)
Bacillus sp. (KS 1)
Alcaligenes sp. (KS 3)
Pseudomonas sp. (KS 5)
Pseudomonas sp. (KS 7)
Corynebacterium sp. (OW 1)
Pseudomonas sp. (OW 6)
Bacillus sp. (OW 8)
Alcaligenes sp. (OS 1)
Alcaligenes sp. (OS 6)
Pseudomonas sp. (OS 9)
Bacillus sp. (YW 1)
Bacillus sp. (YW 4)
Bacillus sp. (YW 7)
Alcaligenes sp. (YS 5) and
Bacillus sp. (YS 8).
Out of 55 isolates 17 isolates was
found to be potent in nitrate
reduction
Nitrate reducing efficiency of bacteria in synthetic medium with
100 mg.L-1 of nitrate at 48 hrs
Growth - 95 x 103 cfu.mL-1 (KW1)
NO3 - 80.2%, 78.9% (KW1, YW4)
Nitrite - 0.75 mg.L-1 (YS8)
Ammonium - 2.8 mg.L-1 (OS 1)
• Based on the above results (> 70%) the following
isolates were selected for further analysis of nitrate
removal.
A - Pseudomonas sp. (KW 1)
B - Bacillus sp. (KS 1)
C - Corynebacterium sp. (OW 1)
D - Pseudomonas sp. (OW 6)
E - Bacillus sp. (OW 8)
F - Alcaligenes sp. (OS 1)
G - Pseudomonas sp. (OS 9)
H - Bacillus sp. (YW 4)
Consortium used for the study
A+B
A+B+C
A+B+C+D
C+G
D+E+F
D+E+F+B
A+C
A+B+D
A+B+C+E
C+H
D+E+G
E+F+G+H
A+D
A+B+E
A+B+C+F
D+E
D+E+H
E+F+G+A
A+E
A+B+F
A+B+C+G
D+F
D+E+A
E+F+G+B
A+F
A+B+G
A+B+C+H
D+G
D+E+B
E+F+G+C
A+G
A+B+H
B+C+D+E
D+H
E+F+G
F+G+H+A
A+H
B+C+D
B+C+D+F
E+F
E+F+H
F+G+H+B
B+C
B+C+E
B+C+D+G
E+G
E+F+A
F+G+H+C
B+D
B+C+F
B+C+D+H
E+H
E+F+B
F+G+H+D
B+E
B+C+G
C+D+E+F
F+G
E+F+C
G+H+A+B
B+F
B+C+H
C+D+E+G
F+H
F+G+H
G+H+A+C
B+G
C+D+E
C+D+E+H
G+H
F+G+A
G+H+A+D
B+H
C+D+F
C+D+E+A
F+G+B
G+H+A+E
C+D
C+D+G
D+E+F+G
F+G+C
H+A+B+D
C+E
C+D+H
D+E+F+H
F+G+D
H+A+B+E
C+F
C+D+A
D+E+F+A
Where
A. Pseudomonas sp. (KW 1) B. Bacillus sp. (KS 1) C. Corynebacterium sp. (OW 1)
D. Pseudomonas sp. (OW 6) E. Bacillus sp. (OW 8) F. Alcaligenes sp. (OS 1)
G. Pseudomonas sp. (OS 9) H. Bacillus sp. (YW 4)
H+A+B+F
Nitrate reduction by consortium
>86% - A+H
45 % - E+F+C
< 29 % - Four
From the study A+H (Pseudomonas sp. (KW1) and
Bacillus sp. (YW4)) consortia showed maximum
nitrate reduction
Selected for further kinetic studies (carbon sources,
temperature, pH, inoculum dosage) on nitrate
removal
Effect of various carbon sources on nitrate
removal
100-0.6 mg.L-1 - Starch
86 x 104 - Starch
Starch - Less
99.4 % reduction
Starch - Less
Effect of various temperatures on nitrate removal in MSM
High Temp - Decreese
> 99 % - 30oC
30oC High reduction
Effect of various pH on nitrate reduction by bacterial consortium (A+H) in
synthetic medium with 100 mg.L-1 of nitrate
6,9 – less, Max-7 (0.6)
9 - less, Max-7
6,9 – less, Max-7 (84.5 x 104 )
6,9 – less, Max-7 (99%)
6 - less, Max-8
Effect of various cell concentrations of bacterial inoculum (A+H)
5% - More
Max- 5% (105), Less – 1% (85)
Max- 5% (0.5
mgL-1)
5% - 99.8, 1%-99.3
2 % - max
Drinking water (10 L) + 100 mg.l-1 of NO3 + Starch (1.0 %) at pH 7
Inoculum (A+H) dosage (1 %)
Reactor (18-20 hrs)
Settling tank
(Coagulants - 15 / 60 min)
Sand filter
Treated water tank
Estimation - Bacterial growth, NO3, NO2 and NH4
6, 12, 18, 24, 30, 36, 42 and 48 hrs
Pilot scale treatment plant (10 litres)
Reservoir
Reactor tank
Settling tank
Filtration tank (55 cm , 60 cm 35 cm)
Collection tank
Pilot scale study for nitrate removal in drinking water
85 x 104 – Max
100-0.5
99 % - Nitrate
3.2 - Nitrite
8.4 - Ammonium
Large scale study in nitrate reduction in
drinking water sample (A+H)
Drinking water (1000 L) + 100 mg.l-1 of NO3 + Starch (1.0 %) at pH 7
Inoculum (A+H) dosage (1 %)
Reactor (18-20 hrs)
Settling tank
(Coagulants - 15 / 60 min)
Sand filter
Treated water tank
Estimation - Bacterial growth, NO3, NO2 and NH4
6, 12, 18, 24, 30, 36, 42 and 48 hrs
Large scale treatment plant setup used for the study
( IVC labs & Environmental Services, Chennai)
10L
1000 L
Package of filter tank
Large pebbles : 2.0 - 2.5 cm (bottom)
Small pebbles : 0.7 - 1.5 cm
Gravel : 0.4 - 0.6 cm
Coarse sand : 0.05 - 0.1 cm
Fine sand : 0.15 -0.3 mm
Activated carbon : 0.75 - 1.0 m
Aeration
75 rpm for 16 – 20 hrs
Large scale treatment plant (1000 litres)
• Every six hours upto 48 hrs water sample was
analysed for NH4, NO2 and NO3.
• The water was collected from the collection tank
after treatment and was subjected to its
physico-chemical and bacteriological quality
and compared with the standards for drinking
water.
Large scale study for nitrate removal by bacterial consortium (A + H)
in drinking water
2.1 – Nitrite
7.6- Ammonium
74 x 104 – Max
100-8
92%
Physico-chemical parameters of water sample before and after
large scale treatment
Untreated
water
Treated
water
ISI drinking
water standard
pH
7.1
7.3
6.5 - 8.5
Conductivity (mS)
11
10
-
Turbidity (NTU)
7
2
5
None
None
Unobjectionable
Total solids
855
240
500
Total hardness
108
15
300
Chloride
13
6
250
Nitrate
100
8
45
Sulphate
0.4
0.05
200
Phosphate
12
0.4
-
74 x 104
16 x 101
-
Parameters
Odour
THB (CFU.mL-1)
All the values are expressed in mg.L-1 except pH, EC and turbidity.
Lab scale anaerobic
reactor
Digester 1 (100 L)
Digester 2 (Temperature shock test - days)
100 ℓ Lab
scale
Feeding
Mode
Intermittent
Feeding
Continuous feeding
Ratio
FW
FW+ SS
(1:9)
FW+ SS
(1:9)
FW+ SS
(2:8)
FW+ SS
(3:7)
FW+ SS
(4:6)
FW+ SS
(5:5)
SS only
(0:10)
Days
1 – 29
30 – 86
87 – 118
119 – 139
140 – 172
173 – 203
204 – 264
265- 356
30 ℓ Lab
scale
HRT
20 days
15 days
10 days
5 days
Days
1 – 182
183 – 244
245 –300
301-336
Shock
load
20oC
(84th day)
40oC
(99th day)
45oC
(155th day)
Parameters
FW+ SS
(1:9)
FW+ SS
(2:8)
FW+ SS
(3:7)
FW+ SS
(4:6)
FW+SS
(5:5)
FW+SS
(0:10)
pH
7.47
(7.19 - 7.61)
7.58
(7.52 – 7.64)
7.70
(7.56 – 7.85)
7.71
(7.64 – 7.81)
7.88
(7.84 – 7.92)
7.63
(7.59 – 7.65)
Biogas
(L/Day)
43.8
(37 - 46)
47.23
(46 - 48)
47.76
(46 – 48)
60.37
(58 - 64)
85.18
(84 - 86)
33.24
(32 - 34)
CH4
(L/Day)
31.49
(27 - 38)
34.73
(33 - 35)
33.32
(31 - 35)
40.07
(34 - 46)
60.07
(57 – 63)
23.72
(21 - 24)
CH4
(L/g VS)
0.162
(0.148–0.169)
0.214
(0.204–0.241)
0.210
(0.192– 0.241)
0.240
(0.193– 0.282)
0.268
(0.251–0.304)
0.195
(0.175–0.210)
CH4
(L/g TCOD)
0.284
(0.213-0.328)
0.381
(0.343-.0411)
0.401
(0.377-0.470)
0.240
(0.179-0.304)
0.371
(0.340-.0389)
0.234
(0.208-0.272)
VS red(%)
49.97
(44.4 – 61.5)
43.59
(39.1 – 52.5)
53.45
(48.8 – 58.7)
57.79
(53.7 – 65.2)
64.98
(64.2 – 68.5)
35.38
(32.2 – 41.2)
SCOD red(%)
60.71
(50.0 – 66.6)
61.44
(51.2 – 69.4)
60.04
(53.1 – 66.6)
68.12
(58.8 – 74.4)
63.57
(56.5 – 66.2)
46.72
(41.1 – 47.3)
TCOD red(%)
58.34
(48.2 – 66.6)
67.69
(53.9 – 75.5)
62.97
(57.4 – 68.6)
53.04
(47.3 – 56.6)
61.58
(57.4 – 67.1)
56.9
(53.8 – 60.0)
FW+SS
(0:10)
Parameters
FW+ SS(1:9)
FW+ SS (2:8)
FW+ SS (3:7)
FW+ SS(4:6)
FW+SS(5:5)
SCOD(mg/L) Inf
14544
(11040-19680)
12480
(11200-16640)
11440
(10240-12480)
13668
(11200-16640)
15197
(14080-15936)
12164
(11832-12268)
SCOD(mg/L)
5163
(3840-5760)
4891
(3840-6720)
4680
(4160-5440)
4342
(3200-6080)
5591
(5248-6720)
6544
(5452-6912)
17978
(14400-22080)
18880
(15360-20480)
17208
TCOD(mg/L) Inf
(15360-20480)
30308
(24320-33920)
32307
(30720-33920)
20753
(18345-21625)
TCOD(mg/L)
7040
(5280-8320)
6293
(3520-8320)
6080
(5440-7360)
14125
(12800-15680)
12370
(10800-13944)
8868
(8352-9766)
Alkali(mg/L) Inf
708
(642 - 940)
535
(480 - 620)
424
(380 - 480)
352
(260 - 428)
320
(260 - 460)
1592
(1480 - 1680)
Alkali(mg/L)
3041
(2740 - 3880)
3066
(2920 - 3160)
3250
(2960 - 3249)
3786
(3660-3880)
5326
(4240 - 5868)
4557
(4500 - 4700)
VFA(mg/L) Inf
660
(586 - 743)
813
(689 - 843)
830
(798 - 956)
3415
(3400 – 3865)
4731
(4234 - 5122)
3060
(3024 - 3124)
VFA(mg/L)
259
(214 - 350)
319
(297 - 371)
357
(267 - 423)
395
(278 - 475)
503
(456 - 521)
344
(326 - 365)
HRT Effect from 30L digester
Parameters
HRT 20 days
HRT 15 days
HRT 10 days
HRT 5 days
pH
7.84 (7.81-7.87)
7.84 (7.81-7.87)
7.76 (7.75-7.79)
7.85 (7.82-7.89)
Biogas(L/Day)
12.92 (12.5-13.3)
13.40 (13.1-13.8)
15.46 (15.1-15.9)
17.24 (16.8-17.8)
Methane(L/Day)
8.77 (7.37-9.80)
9.36 (9.03-10.05)
10.87 (10.85-11.28)
12.48 (11.45-13.97)
CH4(L/g VS)
0.191 (0.138-0.236)
0.231 (0.196-0.265)
0.181 (0.170-0.177)
0.120 (0.111-0.130)
CH4 (L/g TCOD)
0.191 (0.146-0.235)
0.204 (0.188-0.221)
0.159 (0.147-0.177)
0.108 (0.102-0.119)
VS red (%)
45.81 (43.47-48.3)
61.44 (58.4-63.2)
61.46 (57.3-66.2)
54.2 (55.2-56.9)
SCOD red (%)
66.32 (62.5-76.08)
61.34 (59.09-61.98)
57.77 (51.72-63.33)
60.09 (58.33-63.88)
TCOD red (%)
52.30 (43.19-56.52)
62.06 (60.0-63.82)
58.83 (54.54-64.58)
56.04 (52.83-56.60)
SCOD (mg/L) inf
15104 (12800-16000)
13937 (13440-14432)
20385 (19532-21377)
25306 (25113-26107)
SCOD mg/L
5056 (3580-5760)
5360 (4816-5904)
8596 (7673-9676)
10092 (9193-10905)
TCOD(mg/L) inf
28456(27840-31150)
30710 (29520-32336)
33692 (32089-37324)
37342 (36633-37488)
TCOD mg/L
13632 (12800-17600)
11733 (11424-11952)
13868 (11723-16588)
16408 (15312-17680)
Alkali (mg/L) inf
659.5 (578-720)
1449.2 (1420-1460)
1620 (1580-1640)
1615 (1596-1626)
Alkali (mg/L)
4190 (3900-4640)
4523 (4308-4680)
4472 (4260-4680)
5189 (5004-5290)
VFA (mg/L) inf
595.6 (567-638)
577.5 (548-604)
675.04 (645.67-713)
779.5 (768.3-798.6)
VFA - mg/L
305.5 (297-324)
328.27 (312.4-346.1)
354.40 (346.5-375)
360.97 (345.5-386.7)
Saturday, December 22, 2007
Bioremediation patent for Prof. K.M. Elizabeth
• Prof. K.M. Elizabeth of the Department of Microbiology in Gitam
University has succeeded in ammonia removal from industrial
effluents through a bio-remediation method and has obtained a
patent for the method, which will be of use in steel industry in
particular. The inventor claims ' the bacterium identified by him can
remove 100 per cent ammonia within 24 hours, according to
Nessler’s method, and 75 per cent according to the Russian method
of Nesselerisation'. This is an indication of quality research work
done in lesser known universities.
THANK YOU