About Bio-remediation:
- It is defined as the process whereby (mostly) organic wastes can be biologically degraded under controlled conditions to an innocuous state, or to levels below the respective concentration limits, as set by the controlling authorities.
- It uses mainly microorganisms(Bacteria, Fungi), plants or plant enzymes, to detoxify contaminants in the soil and other environments.
- This can involve either aerobic or anaerobic micro-organisms that often use this breakdown as an energy source.
- As it relies on the microbial growth and activity, its effectiveness is highly dependent on the applied environmental parameters that influence the microbial growth and the degradation rate.
- It can mineralize waste material into water, carbon dioxide, biomass, or other nonhazardous products and thus obviate the need for further treatment.
- Application: It can be used to treat:-
- Municipal wastes and process waters;
- suitable (for each case) microorganisms may also be applied for the degradation of pesticides, industrial chemicals, components of crude oil;
- Compounds that, until recently, were regarded as non-biodegradable, such as chlorinated solvents, chlorofluorocarbons, and other synthetic organic compounds.
- Bioremediation technologies can be classified into two general categories: ex situ and in situ.
- Ex-situ technique- It requires the physical removal of the contaminated material and its transportation to another area for further treatment by bioreactors, land farming, or composting
- In-situ technique- It involves treatment of contaminated material in place, such as by bioventing, or biostimulation.
| Bioaugmentation- Addition of bacterial cultures(grown offsite or in the laboratory) to a contaminated medium; frequently used in bioreactors and ex situ systems. Biofilters-Use of microbial stripping columns to treat (mostly) air emissions or odors (volatile compounds). Biosparging– The injection of air under pressure can enhance biological degradation; usually performed in situ; noninvasive. Biostimulation- Stimulation of indigenous microbial populations in soils or groundwater; which can be performed either in situ or ex situ. Bioreactors- Biodegradation in a container or reactor; may be used to treat several liquid wastes or slurries; rapid degradation kinetics but relatively high capital and operational cost. Bioventing- Method of treating contaminated soils by drawing oxygen through the soil to stimulate microbial growth and activity. Composting- Aerobic, thermophilic treatment process; can be performed by using static piles, aerated piles, or continuously fed reactors; low cost but extended treatment time. Land farming- Solid-phase treatment system for contaminated soils; may be performed in situ or in a constructed soil treatment cell; cost-efficient. |
