Definition of Bioremediation
- Bioremediation is defined as a technical process that involves cleaning or abating contamination in a polluted area. It involves the use of biological agents such as bacteria and fungi to clean the pollution.
- It is efficient at clearing contaminants in a particular area.
- The biological agents break down the waste into nutrients and organic matter that pose no harm to the environment or the biodiversity of that area.
Factors That Bioremediation Depends On
- Soil moisture of 25-28% is a prerequisite.
- Low clay or soil content is required.
- Presence of aerobic or anaerobic bacteria.
- Natural biological processes such as catabolism and anabolism.
- Environmental factors like temperature, pH, oxygen content, electron acceptor etc.
- Presence of specific nutrients like carbon, nitrogen etc.
Types of bioremediation
In situ methods
- It occurs in the same place as the polluted area. The main methods under this are –
- Bio venting – is a process where air and nutrients are supplied through wells into the contaminated soil to stimulate the growth and development of microorganisms. It is used for simple hydrocarbons and used when the contamination is deep into the soil.
- Bio sparging – is the process through which there is pressurized injection of air below the ground water table to increase the oxygen concentration in the said are and also enhance the biological degradation process. This process is used to increase mixing in the saturated zone and it is an easy, low-cost process.
- Bioaugmentation – is a process where there is continuous addition of indigenous or exogenous microorganisms to the polluted areas to carry out specific remediation tasks on the site.
Ex situ methods
- The process does not occur in the same place as the contaminated area but there is deliberate relocation of contaminated material.
- Composting – is a process that involves placing the contaminated soil with non-hazardous organic material to enhance the growth of microorganisms naturally such that the soil can be degraded at a faster pace.
- Land farming – is a process in which the polluted soil is spread over an already prepared bed of soil with microorganisms. It is spread at regular intervals and vigorously tilled until the pollutants are degraded.
- Bio piles – is a technique that combines composting and land farming – engineered cells are used to build aerated compost pits. It is used for treating surface contamination by hydrocarbons.
- Bioreactors – is a process used for treatment of contaminated soil and water through an engineered containment system.
