An introduction to bioremediation

1. BIOREMEDIATION
Aman Ullah
B.Sc. Med. Lab. Technology
M. Phil. Microbiology
Certificate in Health Professional Education
Lecturer, Department of Medical Lab.
Technology
Institute of Paramedical Sciences, Khyber
Medical University, Peshawar, Pakistan

2. BIOREMEDIATION
Process that uses microorganisms, fungi, green plants
or their enzymes to return the natural environment
altered by contaminants to its original condition.

3. TYPES OF BIOREMEDIATION
In Situ bioremediation
Clean up approach that involves the direct contact
b/w microorganism and contaminant.
Advantages:
1- Low cost.
2- Minimal site disruption.
3- Simultaneous treatment of contaminated water and soil.
4- Minimal exposure of public and site personnel.

4. Disadvantages:
1- Time consuming.
2- Seasonal variation.
3- Problematic addition of additives.

5. Types of In situ Bioremediation
1- Intrinsic in situ bioremediation.
2- Engineered in situ bioremediation.

6. Intrinsic BR:
Bioremediation that can occur on its own
Factors effecting rate of intrinsic
bioremediation:
1- moisture in soil.
2- pH.
3- Temp
4- Soil nutrients.
5- presence of e acceptors (NO3 , SO4).
6- Toxin conc.

7. Engineered In situ bioremediation:
It can be spurred on via the addition of fertilizers or by
manipulating other components to increase the
bioavailability within the medium (biostimulation).
Recent advancements have also proven successful via the
addition of matched microbe strains to the medium to
enhance the resident microbe population's ability to
break down contaminants (bioaugmentation).

8. Ex Situ Bioremediation
Ex-situ conservation means literally, "off-site
conservation“. It is removal and collection of
waste at a place to facilitates biodegradation.
Classified into
1- Solid phase treatment.
2- slurry phase treatment.

9. Solid phase treatment includes
1- organic wastes.
2- domestic wastes.
3- industrial wastes.
4- agricultural wastes.
The traditional method involves the production
of compost.

10. Composting
It is self heating, substrate dense, managed microbial system
suitable for the treatment of large amount of contaminated
waste. Hazardous compds. reported to be removed by
composting are aromatic hydrocarbons, halogenated compds.
Microbial growth is affected by
1- moisture in soil.
2- pH.
3- Temp
4- Soil nutrients.
5- particle size.
6- Toxin conc.

11. Composting can be done either
1- Open land system: it is in expensive but
difficult to manage.
2- Closed treatment system: Expansive but
manageable.

12. Open land system

13. Closed treatment system

14. Slurry phase system
Contaminated materials, microorganism and
water are formulated into slurry within the
bioreactor or fermentor.
The bioreactors are designed
to promote microbial degradation.

15. Types of slurry phase bioreactors
1- Aerated lagoons
Nutrients are supplied, mixers are fitted for
slurry formation and surface aerators provide air
for microbial growth. Not appropriate for
volatile wastes.

16. 2- Closed system: (low shear air lift reactors)
In this bioreactor pH, temp, nutrient addition,
mixing and oxygen supply can be controlled as
desired. Pretreatment involves
 A-fractionation of solid
 washing
 milling to reduce particle size and slurry
formation.
Certain surfactants like anthracene, pyrene are
added to ennhance rate of biodegradation.

17. Factors affecting slurry phase
biodegradation
1- moisture in soil.
2- pH.
3- Temp.
4- Soil nutrients.
5- Reactor operation.
6- Toxin conc.
7- Microbial population.
8- Mixing (aeration).

18. Questions/Suggestions
khurramthalwi@hotamail.com