Definition of Bioremediation
Bioremediation is the process of removing or utilizing the pollutants from a particularly polluted area (like soil, municipal water tanks or sewage water, oil spills in water, or land) by the help of microorganisms like bacteria, fungi and also plants. It is a type of biotechnical waste management method which uses no harmful chemicals and, in order, protects the Earth and promotes a sustainable environment.
Process of Bioremediation
The microorganisms used in the Bioremediation process degrade the pollutants and convert them into a non-toxic substance or form. The process begins when microorganisms like bacteria, fungi, and small plants, which are used to extract the pollutants, come in contact with the contaminants like oil, etc. The microbes use the contaminants as food. To start the process of bioremediation, the microorganisms need a suitable environment to thrive and do their job. Ideal environment conditions consist of a balanced temperature, availability of moisture, proper levels of surface pH. After the microorganisms are comfortable in their surroundings, they use the contaminants as a source of food. To break down the food consumed, the microbes secrete enzymes, which degrades the contaminants into nutrients. The result of the process ends up with byproducts, are water, carbon dioxide, and non-toxic acids.
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Types of Bioremediation
This type of bioremediation process is done with the help of microorganisms which convert the organic contaminants or metallic contaminants into more chemically inactive forms. The microorganisms break down the compounds and metabolize them. Aerobic bacteria need an oxygen source, and the byproducts at the end of the process are typically water, salts, and carbon dioxide. Anaerobic processes of bioremediation are carried out in the absence of oxygen, and the byproducts of this process are typical, i.e., methane gas, sulfides, hydrogen gas, elemental sulfur.
Phytoremediation is another type of bioremediation that helps eliminate contaminants with the help of plants by repairing and regenerating the soil and ground and surface water. The plants used in the process disseminate the toxic material from the soil and holds on to them within their plant tissues and constrains them until they are broken down at the roots. The plants work by pulling up the contaminants with their roots, which accumulates in the stems. Plants take up the dangerous chemicals from the soil and release them into the air through transpiration and evaporation by the air. A few pollutants which the plants can clean up are metals, pesticides, chlorinated solvents, polychlorinated biphenyls, and petroleum hydrocarbons. Some plants which can be used for phytoremediation are Indian Mustard, Indian Grass, Brown mustard, Sunflower plants, Barley Grass, Pumpkin, Poplar trees, Pine trees, and White Willows. These have rejuvenating and revitalizing characteristics which help the process.
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Fungi are known as nature's decomposers. They break down most of the Earth's plant and hard woody material, resulting in the regeneration of the soil. Fungi use their metabolic enzymes to decompose chemicals like metals and varied types of pesticides. Fungi acts as a catalyst for microorganisms and plants by breaking down the larger hydrocarbon chains into smaller pieces, thereby making their process easy. The fungi suck up the chemicals by breaking them down with the help of enzymes and then store the nutrients in the fleshy parts, which are known as mushrooms.
Bioremediation of Wastewater
Bioremediation of wastewater is an important part of bioremediation. The sewage water can be treated by the processes of bioaugmentation and intrinsic bioremediation. The process is done with the help of microorganisms, which can reach any parts of the contaminated places like municipal water tanks. The aerobic microbes are used in these processes, and the water is aerated to provide oxygen for the bacteria to thrive and grow. The bacteria consume the organic contaminants and moulds the less soluble parts. The byproduct of this process is nitrogen gas, which is later released in the atmosphere.
Question: How is Bioremediation Done by the Microbial Remediation Process? What Type of Fungi can be Used in Remediation, and Which Contaminants Do They Work on?
Answer: The process of Microbial remediation is performed by professionals. They breed bacteria in extremely high numbers and then inject them in the areas that need to be treated. Another way of microbial remediation is by creating an ideal condition for the bacteria in the contaminated soil or water so that it becomes a development habitat for the bacteria. The contaminated area can be transformed into an ideal area for the microbes by changing the temperature, oxygen, and plenty of food supply.
Following are the type of fungi which can be used in remediation along with the information regarding the contaminants they work on: -
1) Shaggy Mane - Works on arsenic, cadmium, and mercury.
2) Elm Oyster - Works on dioxins and wood preservatives.
3) Phoenix Oyster - Works on cadmium, copper, TNT, and mercury.
4) Pearl Oyster - Works on PCBs, mercury, dioxins, PAHs.
Question: State the Advantages and Disadvantages of Bioremediation.
Advantages of Bioremediation: -
With the help of bioremediation, the pollutants contaminating the soil and water can be completely broken down into non-toxic chemicals because there is no use of any chemicals.
The process of bioremediation is accepted publicly throughout the world because it is a natural process and does not harm the Earth.
The equipment used in the process and the cost of treatment using bioremediation is exceptionally low. Also, the equipment required in this process is minimal as compared to other remediation processes.
Disadvantages of Bioremediation: -
If the growth of the microbes is not controlled, it results in uncontrollable amounts of bacteria. This causes the bacteria to not break down the organic contaminants, which results in toxic byproducts.
The process can only work if the contaminated area is suitable for the bacteria to grow properly, and inadequate numbers.
The process takes longer to work and get completed than other remediation technologies.