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

Biosparging

Biostimulation

Bioaugmentation

Phytoremediation

Land farming

Compost

Biopiles

Bioreactors

BioventingThe 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

• 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.

Phytodegradation

• 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

No reduction : -Less reduction : +Moderate reduction : ++High reduction : +++

Nitrate reduction test

Reduction of nitrate / nitrite to ammonium

Appearance of reddish orange colour

Based on intensity of the colour

Potent isolates used for study (+++)

• 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)

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)

A + B A + B + C A + B + C + D

A + C A + B + D A + B + C + E

A + D A + B + E A + B + C + F

A + E A + B + F A + B + C + G

A + F A + B + G A + B + C + H

A + G A + B + H B + C + D + E

A + H B + C + D B + C + D + F

B + C B + C + E B + C + D + G

B + D B + C + F B + C + D + H

B + E B + C + G C + D + E + F

B + F B + C + H C + D + E + G

B + G C + D + E C + D + E + H

B + H C + D + F C + D + E + A

C + D C + D + G D + E + F + G

C + E C + D + H D + E + F + H

C + F C + D + A D + E + F + A

C + G D + E + F D + E + F + B

C + H D + E + G E + F + G + H

D + E D + E + H E + F + G + A

D + F D + E + A E + F + G + B

D + G D + E + B E + F + G + C

D + H E + F + G F + G + H + A

E + F E + F + H F + G + H + B

E + G E + F + A F + G + H + C

E + H E + F + B F + G + H + D

F + G E + F + C G + H + A + B

F + H F + G + H G + H + A + C

G + H F + G + A G + H + A + D

F + G + B G + H + A + E

F + G + C H + A + B + D

F + G + D H + A + B + E

H + A + B + F

Consortium used for the study

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

86 x 104 - Starch 100-0.6 mg.L-1 - Starch

Starch - Less

Starch - Less

99.4 % reduction

Effect of various temperatures on nitrate removal in MSM

High Temp - Decreese30oC High reduction

> 99 % - 30oC

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 (84.5 x 104 )6,9 – less, Max-7 (0.6)

6,9 – less, Max-7 (99%)

9 - less, Max-7

6 - less, Max-8

Effect of various cell concentrations of bacterial inoculum (A+H)

Max- 5% (105), Less – 1% (85) Max- 5% (0.5 mgL-1)5% - More

2 % - max

5% - 99.8, 1%-99.3

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

Estimation - Bacterial growth, NO3, NO2 and NH4

6, 12, 18, 24, 30, 36, 42 and 48 hrs

Treated water tank

Reactor tank

Settling tank

Filtration tank (55 cm , 60 cm 35 cm)

Collection tank

Reservoir

Pilot scale treatment plant (10 litres)

Pilot scale study for nitrate removal in drinking water

85 x 104 – Max100-0.5

3.2 - Nitrite8.4 - Ammonium

99 % - Nitrate

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

Estimation - Bacterial growth, NO3, NO2 and NH4

6, 12, 18, 24, 30, 36, 42 and 48 hrs

Treated water tank

Large scale treatment plant setup used for the study( IVC labs & Environmental Services, Chennai)

1000 L10L

Package of filter tankLarge pebbles : 2.0 - 2.5 cm (bottom)Small pebbles : 0.7 - 1.5 cmGravel : 0.4 - 0.6 cmCoarse sand : 0.05 - 0.1 cmFine sand : 0.15 -0.3 mmActivated carbon : 0.75 - 1.0 m

Aeration75 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

74 x 104 – Max100-8

2.1 – Nitrite7.6- Ammonium

92%

Physico-chemical parameters of water sample before and afterlarge scale treatment

ParametersUntreated

waterTreated

waterISI drinking

water standard

pH 7.1 7.3 6.5 - 8.5

Conductivity (mS) 11 10 -

Turbidity (NTU) 7 2 5

Odour 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 -

THB (CFU.mL-1) 74 x 104 16 x 101 -

All the values are expressed in mg.L-1 except pH, EC and turbidity.

Lab scale anaerobic reactor

100 ℓ Lab scale

30 ℓ Lab scale

Feeding Mode

Intermittent Feeding

Continuous feeding

Ratio FWFW+ 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

Digester 1 (100 L)

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)

Digester 2 (Temperature shock test - days)

ParametersFW+ SS

(1:9)FW+ SS

(2:8)FW+ SS

(3:7)FW+ SS

(4:6)FW+SS

(5:5)FW+SS(0:10)

pH7.47

(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)

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)

SCOD(mg/L) Inf14544

(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)

TCOD(mg/L) Inf17978

(14400-22080)18880

(15360-20480)

17208

(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) Inf708

(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) Inf660

(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)

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)

HRT Effect from 30L digester

Saturday, December 22, 2007Bioremediation 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