The microorganisms have the abilities to degrade, detoxify and even accumulate the harmful organic as well as inorganic compounds. Besides them, higher plants have also been reported to remove such pollutants, primarily through their ability to accumulate these in there tissues.
The objective of bioremediation is to exploit naturally occurring biodegradative processes for Cleanup of the polluted environments. Since the industrial revolution human activities have resulted into the eventual release of large quantities of chemicals to the environment. Cost for cleaning polluted sites using conventional physical or chemical methods is very expensive. It is known that microorganisms are present in almost every environment on Earth and that they are capable of degrading and mineralizing a wide range of organic compounds. Biodegradation is a natural process and costs associated with remediation technologies are less expensive than physical or chemical methods. Bioremediation is more Environment friendly.
Basic principles of bioremediation is natural attenuation, which is defined as naturally occurring processes in the environment that act without human intervention to reduce the mass , toxicity, mobility, volume, or concentration of contaminants in those media.
Bioremediation always competes with alternative technologies for achieving an environmentl cleanup goal. Bioremediation is typically among the least expensive options, with additional important advantage that in many cases bioremediation is a permanent solution to the contamination problem because the contaminant is completely destroyed or sequestered. Bioremediation also has the advantage that it can be relatively nonintrusive to the environment.
Some Technological definations relevant to bioremediation.
Aquifer bioremediation- In situ bioremediation in an aquifer , usually by adding nutrients or cosubstates through injection well.
Aquifer sparging- injection of air into a contaminated aquifer to stimulate aerobic degradation .may also stimulate voltilization .
Bioaugmentation - Addition of exogenous bacteria with defined degradation potential .
Biofiltration - usually an air filter with degrading organisms supported on High surface area support,such as granulated activated carbon or compost.
Biofuffing- Augering soil to increase porosity.
Bioleaching- Extracting metallic contaminants at acid pH,perhaps while attempting to optimise fungal degradation of organic contaminants.
Bioslurping- vacuum extraction of the floating contaminant to and water ,and vapour from the vadose zone. The airflow stimulates biodegradation.
Biotrnsformation - The biological conversion of contaminant to some other form, but not to carbon dioxide and water.
Composting- Addition of biodegradable bulking agent to stimulate Microbial activity. Optimum composting generally involves self heating to 50-60°C .
Constructed wetland- Artificial marsh for bioremediation of contaminated water.
