Bioremediation is a waste operation method that involves the use of organisms to remove or neutralize contaminants from a polluted area. In this article, we’ll discuss them method of bioremediation, factors for microbial bioremediation, types of bioremediation, application of bioremediation, and some bioremediation related technologies.
“Remediate” means to break a problem, and “bioremediate” means to use natural organisms to break an environmental problem similar as defiled soil or groundwater.
Bioremediation means to use a natural remedy to abate or clean up impurity. According to the EPA, it is a “treatment that uses naturally being organisms to break down toxic substances into lower harmed or non-harmed substances”.
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What’s Bioremediation?
It is a natural demeaning process for the treatment of polluted soils, groundwater, or sediments. The process may depend on microorganisms, including bacteria and fungi, to utilize the pollutant (s) as a food source with operating deterioration of the pollutants.
Microorganisms used to perform the function of bioremediation are known as bioremediators.
Bioremediation is one of the most profitable remedial ways presently available. It treats most of the organic energy grounded pollutants such as coal seamen and liquors, petroleum. It also treats some other carcinogenic hydrocarbons like benzene and naphthalene, and some inorganics too.
Essential Factors For Microbial Bioremediation
Several factors are important for microbial remediation. These factors may include:
- Microbial population– suitable kinds of organisms that can biodegrade all kind of the pollutants
- Temperature– applicable temperatures for microbial growth (0 – 40 ˚C)
- Oxygen– to support aerobic biodegradation (around 2 oxygen in the gas phase or 0.4 mg/ liter in the soil water)
- Nutrients– phosphorus, nitrogen, sulfur, and other nutrients to allow the good microbial growth
- Water– soil humidity must be from 50 – 70 of the water holding capacity of the soil
- pH– suitable range is from 6.5 to7.5
Method of Bioremediation
In-situ bioremediation is the treatment (at the site) of polluted material, such as benzene, toluene, and TNT. In ex-situ bioremediation, several ways involve for physical discarding (away from site) of the polluted material. The treatment process results in the protection of environment in various elements , such as Bio-piles and soil treatment unit.
How Does It Work?
Environmentalists examine waste material and insulate certain bacteria, which can ground on their efficiency at digesting and converting the waste. Indigenous or original bacteria are there for use. The bacteria also go through several ways of cultures and procedure for performance testing. The useful bacteria may set back in the waste environment. They grow and thrive in the process condensation and convert the waste into carbon dioxide and water. The right temperature, nutrients, and food also play an important role. Conditions may be refined by adding “amendments.”
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Types Of Bioremediation
Typically, bioremediation is of three types.
1. Biostimulation
In this process, bacteria are allowed to start the process of bioremediation. First the experts release nutrients and other important substances in the soil where there is need to remove the contaminants. These can be present in the form of gas or liquid. The nutrients maximize the growth or development of microorganisms in that site. As a result, bacteria and other microorganisms wash away the contaminants quickly and efficiently.
2. Bioaugmentation
Microorganisms, which can clean up a polluted area, are added to the contaminated soil and water. Bioaugmentation is more commonly operate on contaminants to remove them from the original site, such as municipal waste water treatment facilities.
3. Intrinsic Bioremediation
This process takes place in soil and water because these two places are always full of contaminants and toxins. Intrinsic bioremediation is also called as natural attenuation. It involves use of the microorganisms to remove the harmful substances from soil and water. Especially those sites are present in this method, which are underground, such as underground petroleum tanks.
Advantages of bioremediation
It is a low cost process and needs minimal site disruption. Bioremediation uses low cost than other technologies for cleanup of hazardous waste.
There is simultaneous treatment of the polluted water and soil. It involves minimum exposure to public and can carry out on site, often without causing a major disruption of normal activities. Also, it is used for the complete removal of a wide variety of contaminants.
Disadvantages of bioremediation
The method of bioremediation also has a few disadvantages, such as, not all compounds can undergo rapid and complete degradation. There can be a few complexities about the products of bioremediation, such as, the products may be more persistent or toxic than the original parent compound. The process is quite time consuming.
The addition of additives is also a problem. It is difficult to deduce from bench studies to full scale field operations. Bioremediation applies to those compounds only that are biodegradable as it has seasonal variation.
Applications of Bioremediation
Bioremediation has following applications:
- Removal of artificial waste trials
- Slurry- phase bioremediation is useful too but only for small quantities of polluted soil.
- Bioremediation of aquifer Novel lab degree investigation
- Environmental cleanup
- Bioremediation of polluted soil
- Composting to use for degradation of the household wastes
- Bioremediation of marine oil
Bioremediation of contaminated Soil
In-situ bioremediation of contaminated soil is a treatment of a large volume of soil at formerly. The process is substantially effective at places with flaxen soils. Results may change, mainly depends on the technique of supplying oxygen or electron benefactors to the organisms that destroy the pollutants. Three generally used in-situ approaches include
- Bioventing
- Injection of hydrogen peroxide or oxygen releasing emulsion (ORC) for aerobic treatment
- Injection of HRC for anaerobic treatment
Ex-situ bioremediation of soil involves excavation of the polluted soil. Either located on the site or away from the site, treatment starts in a treatment factory. This approach can be briskly, easier to control, and used to treat a wider range of pollutants and soil types than in-situ approach. Ex-situ bioremediation can be enforced as slurry- phase bioremediation, or solid- phase bioremediation.
Bioremediation of Aquifer
In situ bioremediation (ISB) of groundwater involves the stimulant of indigenous bacterial populations. The process metabolizes target pollutants through the addition of colorful emendations (biostimulation) to the underground environment. Other than emendations, environmentalists may add a few strains of bacteria to the subsurface to help treat some spots (bioaugmentation).
Bacteria bring about coupled oxidation or reduction (redox) responses to survive. Bioremediation degrades such responses to remove pollutants from polluted media (groundwater). Bacteria can use different electron acceptors (oxidized composites) and benefactors (reduced composites) in the three major oxidation pathways;
- Aerobic respiration
- Anaerobic respiration
- Fermentation
ISB can use all of these pathways, and pollutant degeneration may go on through;
- Direct metabolism
- Co-metabolism
- Abiotic conversions that may operate from natural activities
Bioremediation of Marine Oil Spills
It is a useful process for taking off marine oil pollutants. The operation of oleophilic toxin is a useful method of bioremediation. Marine oil spills are veritably disastrous events which pose a great trouble on the affected environment.
Marine oil spills are substantially oils, petroleum, or fuel, composed of intricate hydrocarbons. It involves addition of microbial seeding or inoculum that is able of demeaning hydrocarbons. Utmost microorganisms may set down for seeding is attained from fortified cultures (from an already polluted site). After inoculum addition, there is an addition of toxin. Also environmental alteration happens, like, a sufficient aeration in which nutrient source is a prerequisite.
Marine oil spills treatment can be carried out in two different ways, depending on the case at hand. This includes bioaugmentation such as introducing oil demeaning microorganisms to the affected point. Also biostimulation, which involves adding supplemental nutrients to the affected point to help the subsisting oil degrading microorganisms.
Bioremediation related technologies
A few technologies related to bioremediation are:
• Bioleaching-the extraction of metals from their ores through the application of living organisms.
• Vermicomposting– using chromatic worms, generally red wigglers, white worms, and other earthworms. It produces a miscellaneous mixture of decaying vegetable or food waste, and seeding stuff.
• Bioreactor-any manufactured or manipulated device to support a biologically active environment.
• Rhizofiltration-is a form of phytoremediation. The process involves filtering water through a mass of roots to remove poisonous substances or surplus nutrients.
• Bioventing-an in situ remediation technology that uses microorganisms to biodegrade organic ingredients in the groundwater system.
• Phytoremediation– through the use of plants it alleviates the environmental trouble without the need to dig the pollutant material and dispose of it away.
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